Belgium 2026 Relies on Teenage Full-Backs to Replace Retired 2022 Spine

When Belgium exited the 2022 World Cup in the group stage, the post-match analysis was harsh. A squad that had spent eight years atop the FIFA rankings looked old, slow, and tactically rigid. By 2026, almost all of that spine had retired from international football. What remains is a team built around teenage full-backs, a reshuffled midfield, and a coach betting that speed and energy can compensate for lost experience.

The 2022 Spine Retires, Leaving a Gap

Eden Hazard announced his international retirement in early 2023, closing a chapter that had flickered rather than blazed at the previous World Cup. Kevin De Bruyne followed in 2024 after 104 caps, citing a desire to focus on club football. Romelu Lukaku's last competitive minutes in a Belgium shirt came during Euro 2024, where a hamstring injury limited him to two substitute appearances. Jan Vertonghen and Toby Alderweireld ended their national-team careers after the 2023 Nations League finals, taking with them over 250 caps of defensive composure. The most damaging departure, however, was Thibaut Courtois. A public dispute with coach Domenico Tedesco in 2023—stemming from the captaincy armband—led to the goalkeeper ruling himself out of the 2026 squad. Courtois had been Belgium's best player at the 2018 World Cup, and his absence leaves a void. Koen Casteels, now 33, is the likely starter, but he has only 25 caps and has never faced a knockout-stage penalty shootout. By the start of 2025, Belgium had lost seven players who had started at least three matches in the 2022 tournament. The average age of the squad that faced Austria in the first qualifier was 24.7, down from 30.4 two years earlier. Tedesco described the transition as "necessary but not painless" in a press conference last September. The pain, he suggested, would come from opponents targeting the new defence's inexperience. The scale of the rebuild becomes clear when you compare the 2022 and 2026 projected lineups. In Qatar, Belgium fielded a back four with an average age of 32. In 2026, that figure drops to 22.5. The midfield loses De Bruyne's vision and Hazard's dribbling, but gains the energy of Amadou Onana and the progressive passing of Arthur Vermeeren—though Vermeeren now plays at right-back.

Teenage Full-Backs Emerge as Tactical Solution

Jorthy Mokio made his senior debut for Belgium at 17 years and 8 months during a Nations League match against Wales in March 2025. The left-back, who had only 15 first-team appearances for Ajax at the time, was thrown into a high-stakes qualifier and produced a performance that surprised even Tedesco. He completed 4 dribbles, made 6 recoveries, and won 3 aerial duels. By the end of the qualifying campaign, Mokio had started 6 of Belgium's 8 matches. Arthur Vermeeren's shift to right-back was more gradual. Originally a central midfielder at Antwerp, the 20-year-old had played as a defensive midfielder for RB Leipzig before Tedesco experimented with him at full-back during a friendly against Sweden in November 2024. The reasoning was simple: Vermeeren's passing range and vision could help Belgium build from deeper positions, while his defensive work rate—averaging 6.8 progressive carries per 90 in qualifiers—allowed him to drive forward into midfield transitions. The tactical logic behind starting two teenagers in a World Cup defence is rooted in Tedesco's high-pressing system. Belgium's defensive line sits around 38 metres from goal, roughly 5 metres higher than under previous coach Roberto Martinez. This requires full-backs who can recover quickly when opponents break the press. Mokio's speed—he recorded a top sprint of 34.2 km/h in a qualifier against Romania—and Vermeeren's anticipation make them suited to this role, even if their positional discipline occasionally falters. Critics point out that both players have limited top-level experience. Mokio had only 22 senior club appearances before the World Cup squad was announced. Vermeeren, though more experienced with 58 matches, has played right-back for only 18 of them. Tedesco's response is that the system protects them: the midfield trio of Onana, Tielemans, and Charles De Ketelaere provides cover, and the centre-backs—Wout Faes and Zeno Debast—are instructed to step wide when full-backs push forward.

Qualifying Campaign: Young Defence Holds Firm

Belgium's qualifying record for the 2026 World Cup was strong on paper: 7 wins, 1 draw, 22 goals scored, and only 4 conceded. The draw came in a goalless match away to Wales, where Belgium dominated possession (68%) but lacked a cutting edge. The four goals against were spread across three matches—a 2-0 win over Austria, a 1-0 win over Wales, and a 2-0 win over Romania—suggesting the defence was rarely breached more than once per game. The underlying numbers are encouraging. Belgium's expected goals against (xGA) per 90 minutes dropped to 0.89 in the 2026 qualifying cycle, down from 1.12 in the 2022 cycle. This improvement is largely due to the high press limiting opponents' shot quality: the average shot faced was from 18.3 metres out, compared to 15.7 metres in 2022. Mokio and Vermeeren contributed to this by reducing the number of crosses allowed from their flanks—Belgium conceded only 2.1 crosses per match from the left side, the lowest in their qualifying group. Clean sheets against Austria (2-0) and Wales (1-0) were particularly notable because both opponents attempted to exploit the full-backs' inexperience. Austria's Xaver Schlager repeatedly tried to isolate Mokio in one-on-one situations, but the teenager won 4 of 5 defensive duels in that match. Wales targeted Vermeeren's positioning with diagonal switches, but the right-back's reading of the game—he made 3 interceptions—nullified the threat. Still, the sample size is small. Belgium faced only two top-20 ranked teams in qualifying (Austria, ranked 16th, and Wales, ranked 19th). Uruguay, their first opponent in Group H, is ranked 7th and presents a different challenge. The real test of the young defence will come in the knockout stages, where set-piece vulnerability and penalty shootout pressure could expose their lack of experience.

Senior Core Shifts to Attacking Midfield

With the old guard gone, Belgium's creative burden falls on a midfield that averages 24.7 years of age. Youri Tielemans, now 29, wears the captain's armband and has become the team's primary playmaker from deep. His passing range—he completed 8.2 long balls per 90 in qualifying—allows Belgium to switch play quickly, bypassing pressure. Tielemans also contributed 3 goals in qualifying, including a 30-yard strike against Romania that was the team's goal of the campaign. Amadou Onana, 24, anchors the midfield with a physicality that Belgium lacked in 2022. He averages 3.4 tackles and 2.1 interceptions per 90, and his 6-foot-5 frame makes him a threat at set pieces—though Belgium's set-piece efficiency has been inconsistent. Onana's partnership with Tielemans has developed over 22 matches, and their complementary styles—Tielemans the passer, Onana the destroyer—give Tedesco tactical flexibility. Wide areas are covered by Jeremy Doku and Johan Bakayoko, both 23. Doku's dribbling—he completed 5.6 take-ons per 90 in qualifying—stretches defences and creates space for others. Bakayoko, more direct, averages 0.45 expected assists per 90 and has developed a strong understanding with Vermeeren on the right flank. Up front, Lois Openda leads the line after scoring 12 goals in qualifying, including a hat-trick against Austria. Openda's movement off the shoulder suits Belgium's quick transitions, but his finishing can be erratic—he underperformed his xG by 1.4 goals in qualifying. The midfield average age drop from 30.4 to 24.7 is striking, but it comes with a trade-off. The team lacks a player who can control the tempo in tight knockout matches. Tielemans is capable, but he has struggled in high-pressure club environments—his form at Aston Villa has been inconsistent. Onana is still developing his decision-making. Tedesco's hope is that the collective energy of the group compensates for the absence of a single metronomic presence.

Set-Piece Vulnerability Remains a Concern

Belgium conceded two set-piece goals in qualifying, both from defensive errors by the young full-backs. Against Sweden in a friendly, Mokio lost his marker on a corner, allowing Alexander Isak to score with a free header. Against Romania in a qualifier, Vermeeren misjudged the flight of a free kick, leaving his near post exposed for a looping finish. These moments have become a focus of Tedesco's preparation. Since March 2026, Belgium has added a 25-minute daily set-piece drill to every training session. The drills, designed by assistant coach Alex Gross, focus on zonal marking adjustments and goalkeeper communication. Casteels has been given authority to organise the wall and call out switches, but his own set-piece record—he has saved only 2 of the last 16 penalties he has faced—adds another layer of risk. The data suggests set-piece vulnerability is a systemic issue, not just a full-back problem. Belgium ranked 14th among 32 qualified teams in set-piece xGA during qualifying. Their zonal marking system leaves gaps between the first and second lines, and opponents have exploited this by placing blockers near the near post. Uruguay, their first Group H opponent, scored 4 set-piece goals in South American qualifying, the most of any team in their region. Tedesco acknowledged the issue in a press conference in May 2026: "We know it's an area where we can be punished. We've worked on it, but the proof will be in the tournament." The coach's honesty is refreshing, but it also signals that opponents will target this weakness. If Belgium concede a cheap set-piece goal in a knockout match, the narrative will shift from youthful promise to tactical naivety.

World Cup Draw Places Belgium in Group H

The draw placed Belgium in Group H alongside Uruguay, Iran, and New Zealand. The opener against Uruguay on June 15 in Riyadh is widely seen as the group decider. Uruguay's press triggers, as analysed in a related article on this site, depend on Darwin Núñez's lateral recovery runs, which could test Mokio's positioning and recovery speed. Uruguay also have a strong set-piece record, compounding Belgium's vulnerability. Iran and New Zealand present different challenges. Iran are organised and physical, likely to sit deep and counter. New Zealand, under new coach Darren Bazeley, press aggressively and have a threat from set pieces. Belgium should have enough quality to progress, but the margin for error is slim. If they slip against Uruguay, the knockout path could include France or Brazil in the quarter-final—a daunting prospect for a defence with two teenage full-backs. Belgium's expected threat (xT) ranking among the eight groups is 4th, according to data from Opta. This is below Germany, France, Brazil, and Argentina, but above England and Spain. The ranking reflects the uncertainty around the defence: if Mokio and Vermeeren perform, Belgium could exceed expectations; if they crack, an early exit is possible. The fixture list is kind in one sense: Belgium play Iran in their second match, giving them a chance to rest key players if they beat Uruguay. But the heat in Riyadh—temperatures could reach 38 degrees Celsius—will test the young squad's fitness. Tedesco has rotated heavily during qualifiers, but tournament football demands consistency. The full-backs will need to play every minute unless injury strikes.

Tedesco's Bet: Youth Over Experience

Belgium's 26-man squad includes only three players over 30: Casteels, Tielemans, and defender Brandon Mechele. Mokio and Vermeeren are the youngest outfield players at the entire World Cup, a fact that has drawn both praise and concern. Tedesco's mantra, repeated in a press conference in May 2026, is "Trust the process"—a phrase that has become the team's unofficial slogan. The average squad age of 25.8 is the lowest Belgium has taken to a World Cup since 2006, when a young team featuring Kompany, Fellaini, and Vertonghen reached the round of 16. That team also relied on inexperienced defenders—Kompany was 20, Vertonghen 19—and they were eliminated by Portugal after a late goal. The parallels are striking, and the outcome will hinge on how quickly the 2026 full-backs learn. Success for Belgium in 2026 probably depends on the full-backs' composure in high-stakes knockout matches. If Mokio can handle the pressure of marking a world-class winger, and if Vermeeren can maintain his passing accuracy under a high press, Belgium's attacking assets—Doku, Openda, Tielemans—could carry them deep into the tournament. If not, the rebuild will be judged as premature. Tedesco's bet is not without logic. The 2022 squad was too old and too slow to compete with the tournament's elite. By 2026, a younger, faster team has a higher ceiling, even if the floor is lower. The question is whether the floor will be exposed in the group stage or whether the team can grow into the tournament. For a nation that has never won the World Cup, the answer will unfold over the coming weeks in Riyadh.

Additional Analysis: Comparisons with Other Youthful Squads

Belgium's approach mirrors that of England in 2018, when Gareth Southgate selected a young squad that reached the semi-finals. England's average age was 26.0, slightly older than Belgium's 25.8. Key differences include Belgium's reliance on two teenage full-backs, whereas England had experienced full-backs like Kyle Walker (28) and Danny Rose (27). However, England's centre-backs were young—Harry Maguire was 25, John Stones 24—and they coped well under pressure. Another comparison is Germany in 2010, when they fielded a young squad (average age 25.4) that finished third. Germany's full-backs, Philipp Lahm (26) and Jérôme Boateng (21), were more experienced than Belgium's pair. Yet Lahm and Boateng had combined for only 50 caps before the tournament, similar to Mokio and Vermeeren's combined 35. Germany's success came from a cohesive system and strong midfield leadership, much like Belgium hopes for from Tielemans and Onana. However, Germany also had a reliable goalkeeper in Manuel Neuer (24), whereas Belgium's Casteels is older but less proven. These examples show that youth can succeed, but the margin for error is small.

Potential Impact of Group Stage Fixtures

Belgium's group stage schedule offers a gradual ramp-up in difficulty. They face Iran first, a team that relies on defensive organization and counter-attacks. Iran's main threat comes from set pieces and long balls over the top, which could test Mokio's aerial ability and Vermeeren's positioning. In their second match, Belgium play New Zealand, who are less experienced but physically robust. New Zealand's high press could force errors from the young full-backs, especially if the heat takes a toll. The final group match against Uruguay will likely decide the group winner. Uruguay's attacking trio of Darwin Núñez, Facundo Pellistri, and Federico Valverde will test Belgium's defensive structure. If Belgium can secure at least four points from the first two matches, they can approach the Uruguay game with less pressure. However, a loss to Iran or a draw with New Zealand would create a must-win scenario against Uruguay, which could expose the team's inexperience under pressure.

Key Individual Matchups to Watch

Several one-on-one battles will define Belgium's tournament. Mokio vs. Núñez is the most critical. Núñez's lateral runs and physicality could overwhelm Mokio if he fails to track him. Vermeeren vs. Pellistri is another key duel; Pellistri's direct dribbling and pace require Vermeeren to stay goal-side and avoid diving in. In midfield, Onana vs. Valverde will be a battle of energy and passing range. Onana's physicality can disrupt Valverde's rhythm, but Valverde's experience in big matches gives him an edge. Up front, Openda vs. Uruguay's centre-backs, José María Giménez and Ronald Araújo, will test Openda's movement and finishing. Araújo's recovery speed could nullify Openda's runs behind the defence. These individual battles will likely determine whether Belgium's young squad can compete with top-tier opposition.

Conclusion: A Tournament of Uncertainty

Belgium enters the 2026 World Cup as one of the most unpredictable teams. Their attacking talent is undeniable, but their defensive inexperience and set-piece vulnerability create a high-risk profile. The group stage will reveal whether the young full-backs can handle the pressure of tournament football. If they succeed, Belgium could surprise the world. If they falter, the rebuild will face harsh criticism. Either way, the tournament will provide a definitive answer on Tedesco's bold strategy.