Qatar’s World Cup has seen the biggest upsets in recent history

Editor’s note (December 10th): This article has been updated since it was published.

AS UNDERDOGS THEY overcame Belgium and Spain. And in the biggest upset in a World Cup knockout match this century, Morocco beat Portugal on December 10th for a place in the semi-finals. Bookies had given them just a 16% chance of winning. Despite much criticism of Qatar’s World Cup, the football is captivating fans. So much so that Gianni Infantino, the much-derided president of FIFA, described the first 48 matches in the group stage of the tournament as the “best ever”, pointing in particular to “small teams beating big teams”. Whether this World Cup really is the “best ever” is a matter of opinion (a vested one, in Mr Infantino’s case). But one aspect is quantifiable: the surprises. Have there been more upsets in this World Cup?

The answer seems to be yes. According to data compiled by The Economist this tournament has featured an unusual number of shocks relative to every tournament since 2002. To quantify this, we compiled odds data for the past six World Cups from oddsportal, an odds-comparison website. Pre-match odds reflect the probability of a result as estimated by bookies and punters (large volumes placed on a team will drive down the odds). For example, when Saudi Arabia beat Argentina on the third day of the competition, they were 25-to-1 longshots to do so. That implied they had less than a 4% chance of winning, making it the biggest upset of the past six World Cups. Indeed, of the ten least probable results since 2002, according to the bookies’ pre-match estimates, five were in Qatar. Australia, for instance, were only given around 14% chance of beating Denmark. Likewise Japan, when they beat Germany and then Spain.

What lies behind the shocks? One explanation could be that underdogs were simply underrated ahead of this tournament. Saudi Arabia’s team, for instance, comprised players from the lesser-known Saudi league, making it difficult for punters to form a true assessment of their potential. Smaller teams are also benefiting from the game’s globalisation. Many of Japan’s players now play in top European leagues, for example, exposing them to better training and tactics.

The best explanation, though, may just be the nature of football. It is one of the few sports where dominance need not translate to victory. When Germany lost to Japan, for instance, their expected goals (xG), a measure that assesses the quality of the scoring opportunities they created, was far higher than Japan’s. Indeed Germany’s xG across the three matches they played was the highest of any team in the competition. They failed to qualify out of their group because they fluffed their lines in front of the goal. That one moment can change the outcome of a match keeps underdogs going and keeps fans watching.

Upsets tend to get rarer as the tournament progresses. Even when South Korea famously knocked out Italy and Spain to reach the semi-finals in 2002, they were not the overwhelming underdogs, at least according to the bookies who had given them a roughly 25% chance of winning within 90 minutes (the Koreans needed extra time and penalties to secure their win). Smaller teams struggle to replicate their heroic efforts; stronger teams can suddenly find their stride. Performances, especially in front of the goal, converge back to the mean as they miss fewer chances. But Morocco’s win shows that it is not over for the underdogs yet.■

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