What Will Be the Biggest Upset at World Cup 2026?

The expansion from 32 to 48 teams adds ~16 teams that would not have qualified under the previous format. Many of these teams come from CONCACAF, AFC, CAF, and OFC confederations with less competitive football infrastructure. However, these teams often play with nothing to lose in group-stage matches against favorites, creating the conditions for shock results. In the 2022 World Cup with just 32 teams, there were 5 major upsets (Saudi Arabia vs. Argentina, Japan vs. Germany, Japan vs. Spain, Cameroon vs. Brazil, South Korea vs. Portugal). Extrapolating to 104 matches, 8-12 major upsets are statistically expected in 2026.

World Cup history is defined by upsets. In every single edition since 1990, at least one major favorite has been eliminated in the group stage: Germany (2018, 2022), Spain (2014, 2022), Italy (2010, 2014), France (2002, 2010), Argentina (2002). The probability of at least one top-5 ranked team being eliminated in the group stage is approximately 45% based on historical data. The expanded format, with more matches and more variance, likely pushes this above 50% in 2026.

The tournament's North American venues span multiple climate zones — from the heat and humidity of Houston and Miami to the altitude of Mexico City (2,240m) and the temperate conditions of Seattle and Toronto. European and South American teams unfamiliar with these conditions may struggle, particularly in early group matches when acclimatization is incomplete. CONCACAF teams (Mexico, USA, Canada, Costa Rica, Jamaica) have a natural advantage, potentially causing upsets against higher-ranked opposition.

The 2025-26 club season is one of the longest in football history, with the expanded Champions League format running later into June. Star players from elite clubs like Real Madrid, Manchester City, and PSG will arrive at the World Cup with significantly more minutes in their legs than players from lower-profile leagues. This fatigue gap means that group-stage matches in the first week — when stars are most exhausted — present the highest upset probability. Saudi Arabia's 2022 victory over Argentina came on matchday 1, a pattern that may repeat.

The 48-team format is unprecedented, meaning bookmakers have limited historical data to price matches accurately. New qualifying nations have thin form profiles that are difficult to model. This creates pricing inefficiencies — particularly on match result and correct score markets — that sharp bettors can exploit. First-time World Cup participants are historically underpriced in their opening matches, as bookmakers tend to overweight FIFA rankings and underweight tournament-specific factors like motivation and crowd support.

“Bet365's risk management team has built increased upset probability into their group-stage pricing. They note that match result margins in 2026 group games will be tighter than in any previous World Cup due to the format expansion. Their models suggest 5-8 results where a team ranked 20+ places below their opponent wins, compared to 3-5 in 2022.”

Source: Bet365 Sportsbook

“Betfair exchange volume on underdog match bets has increased 40% compared to the equivalent pre-tournament period for the 2022 World Cup. Sharp bettors are systematically backing lower-ranked teams in early group matches at longer odds, a strategy that has been profitable across the last 3 World Cup cycles.”

Source: Betfair Exchange

“ESPN's simulation model, running 10,000 tournament iterations, projects a 52% probability that at least one of the 5 highest-ranked teams will fail to advance from the group stage. The model identifies Germany, Spain, and Portugal as most vulnerable to group-stage upsets due to the combination of their likely group compositions and historical patterns of inconsistency in opening matches.”

Source: ESPN Analytics / FiveThirtyEight

“Opta's historical analysis shows that first-time World Cup participants win 23% of their opening group-stage matches — higher than most casual bettors would expect. These teams benefit from the element of surprise, high motivation, and opponents' lack of familiarity with their style. With several first-time participants in 2026, at least 1-2 shock results from debutants are statistically likely.”

Source: Opta / Stats Perform