Football is one of the most unpredictable sports in the world. You can never truly know what is going to happen, especially in the best leagues in the world. Although the most successful clubs will usually be billed as favourites, they don't win every time.

From the Premier League and FA Cup to the World Cup and European Championship, the 'beautiful game' brings in viewers from around the globe. The excitement, anticipation and drama can not be topped by any other sport in the world, which is why it is the most popular game on the globe. That sense of unexpectedness is felt in every single campaign.

There have been surprise results since the dawn of the sport. Preston North End were so confident of winning the 1888 FA Cup that the team posed for a photograph with the trophy ahead of the final. They promptly lost to West Bromwich Albion. Here are the greatest shocks any team has ever pulled off to showcase the unpredictable beauty of football.

Ranking Factors

• Quality gap - The wider the chasm in levels between the two teams, the bigger the upset.
• Size of competition - Shocks that are pulled off on the biggest stages are ranked more highly.
• Expectations - The pre-game predictions for the underdog form the basis of the rankings.

9 Bayer Leverkusen's Unbeaten Domestic Season

2023/24 Bundesliga

Bayer Leverkusen defied logic to win the Bundesliga and DFB-Pokal without tasting defeat throughout the 2023/24 campaign. The unheralded club based on the banks of the Rhine were tipped to potentially qualify for the Champions League, but from the first match to the last, they were one of the best teams in Europe. Under Xabi Alonso's leadership, who is one of the most highly regarded coaches in the world, they played exciting and attacking football that no one had believed to be possible.

Leverkusen comfortably secured Bundesliga glory for the first time in their history with a handful of games remaining, before beating Kaiserslautern in the DFB-Pokal final. They did go on to lose the Europa League final 3-0 to Atalanta, but it took nothing away from their overall achievements.

8 Liverpool 0-1 Wimbledon

1988 FA Cup Final

Wimbledon were seventh in England's top-flight, while Liverpool sat top at the end of the 1987/88 season, so the Dons' FA Cup triumph might not seem like a crazy upset. However, with the South London club famous for their rough style, it quickly became a story of them dominating everyone through the football leagues.

Liverpool played a completely different style of football which was far easier on the eye, winning the support of many neutrals. They were the dominant force in the 1980s; Kenny Dalgish's side had romped to the Division One title and hoped to add the FA Cup to their trophy haul. Wimbledon spoiled that plan. Lawrie Sanchez scored a stunning header to give his side a first-half lead which he and his dogged teammates managed to hold onto. BBC commentator John Motson met the final whistle with an iconic yelp: "The Crazy Gang have beaten the Culture Club."

7 USA 1-0 England

1950 World Cup

Going back decades, the USA completed a remarkable upset at the 1950 World Cup. After winning their first group stage match 2-0 against Chile, England were expected to cruise past their opponents from the other side of the Atlantic, but what followed shocked the world. To provide an extra layer of context, the USA had conceded 45 goals across seven successive defeats leading into their World Cup match against the Three Lions.

The team of amateur and semi-professional players pulled off a shock 1-0 victory. The goal was scored by Joe Gaetjens, an accounting student who also washed dishes in a restaurant. It's forever remained a painful day for England, even if it happened more than 70 years ago.

6 Denmark 2-0 Germany

Euro 1992 Final

Denmark only appeared at Euro 1992 because Yugoslavia were expelled from the tournament a few weeks beforehand. Naturally, they were expected to struggle; the odd analyst predicted them to reach the knockout stages, but no one thought they would win it. However, the Danes finished second in their group thanks to a draw with England and a 2-1 win over the French, which saw them start to dream.

Richard Moller Nielsen's team beat the Netherlands on penalties in the semi-finals and then comprehensively outplayed the Germans in the final, earning a 2-0 win. A final goal from Kim Vilfort sealed a memorable victory. It's the greatest night in the nation's sporting history — and they came close to replicating it at Euro 2020.

5 Wigan 1-0 Manchester City

2013 FA Cup Final

The FA Cup is the oldest competition in the world. It is full of history — and drama. For lower-league teams, it stages the most important matches on the calendar, offering a financial lifeline. In 2013, Wigan Athletic were fighting for their lives at the bottom of the Premier League; they were eventually relegated, but their FA Cup triumph made it one of their most memorable seasons.

Manchester City were expected to cruise past Wigan in the final, but the build-up to the game was not ideal for the Cityzens. It was dominated by the news circulating that Manuel Pellegrini was set to replace Roberto Mancini as manager. Wigan, despite riding their luck in the final, took advantage of City's nerves. Pablo Zabaleta saw red, to give the Latics more hope of pulling off a famous win. In the end, Ben Watson headed home from a corner to be the hero.

4 England 1-2 Iceland

Euro 2016

England are on the wrong end of this list twice. Maybe it sums up their international luck — and their darkest hour came in 2016. In the south of France, the travelling English fans were having the time of their lives, but that quickly ended with a defeat to Iceland in the second round of Euro 2016.

After scraping through the group stage, the Three Lions were still expected to cruise past the minnows. When Wayne Rooney, one of the greatest English players of all time, gave them the lead, everything seemed to be comfortable, but two quickfire goals from Iceland delivered a sucker-punch to England's glass jaw. From that point onwards, the tiny nation defended valiantly as the Three Lions failed to muster a meaningful chance. Roy Hodgson resigned at full-time out of embarrassment more than anything else.

3 Saudi Arabia 2-1 Argentina

2022 World Cup

Saudi Arabia's shock win against Argentina at the 2022 World Cup had to feature on this list. The Asian giants' record at World Cups has never been impressive — which is mildly surprising considering the success of their club sides in continental competitions. As the group stages kicked off, Argentina were the firm favourites for the entire tournament, let alone the opening game, but they were quickly given the fright of their lives.

Lionel Messi, one of the greatest players of all time, opened the scoring with a penalty in the 10 minute before Saleh Al Shehri and Salem Al Dawsari gave Saudi Arabia the lead in the second half. Argentina were unable to hit back, leading to stunning celebrations in the crowd. No one could truly believe it, yet the South American nation recovered to eventually win the tournament.

2 Greece 1-0 Portugal

Euro 2004 Final

The Euros is one of the hardest competitions in the world to win. It requires immense luck and skill, but in 2004, Greece provided hope to the rest of the continent that anything is possible. Host nation, Portugal, who had a young and eager Cristiano Ronaldo, were expected to win the tournament, particularly after beating England in the quarter-finals.

It all went wrong in the showpiece fixture. A 57th-minute goal from Werder Bremen forward Angelos Charisteas gave Greece the lead and silenced the home crowd, before they held on until full-time despite Portugal's best efforts. They were champions of Europe and it was almost unbelievable.

1 Leicester's Premier League Title

2015/16 Premier League

On a list dominated by individual matches, Leicester City top the rankings with their 38-game-long upset throughout the 2015/16 Premier League season. The Foxes, who narrowly avoided relegation in the previous season, were given odds of 5,000-1 to win the title at the start of the campaign.

They defied the bookmakers to finish top of the table, 10 points ahead of Arsenal in second place. From start to finish, the likes of Jamie Vardy, Riyad Mahrez and N'Golo Kante toyed with the opposition as if it were a training match. Claudio Ranieri cemented his legacy as one of the greatest Italian managers in Premier League history, whilst the fans revelled in a once-in-a-lifetime moment.