It doesn't happen often and is becoming even less frequent as money dominates the modern game, but there are still some surprises in football.
Cup competitions have always afforded an opportunity to the smaller sides. In one-off knockout matches or ties, upsets are more likely.
In league championships, the stronger squads usually rise to the top over a long season, which means money talks. Nine times out of 10, the big clubs claim the title.
But not always. Every few years, there is an underdog story somewhere in the football world and here is a look at some of the most surprising league winners...
32. Istanbul Basaksehir
Istanbul clubs have dominated Turkish football in the modern era, with Galatasaray, Besiktas and Fenerbahce winning almost all of the titles.
But in 2019/20, there was a new champion from Europe's most populous city as Istanbul Basaksehir came out on top. The club from the Basaksehir region, founded in 1990, finished four points ahead of Tranzonspor.
31. Aston Villa
Aston Villa are seven-times champions of England, but six of those successes came in the very early days of the competition – between 1894 and 1910.
The Villans had to wait another 71 years for their seventh championship. It arrived in 1980/81 as the Birmingham club finished four points above Ipswich, with Arsenal third and West Brom fourth. And Villa went on to win the European Cup the following year, beating Bayern Munich in the final.
30. Atletico Madrid
Atletico Madrid may be Spain's third-biggest club, but the Rojiblancos were nowhere near winning La Liga for a decade and a half after their double success in 1995/96.
Diego Simeone was in the team back then and the former Argentina midfielder returned in 2011 to revive the club's fortunes as coach. Up against Lionel Messi's Barcelona and Cristiano Ronaldo's Real Madrid, Atleti came out on top to win La Liga in 2013/14 – edging out the Catalans with a draw at Camp Nou on the final day.
29. Tijuana
Club Tijuana are a new phenomenon in Mexico. Founded in 2007, the Baja California outfit gained promotion to the Liga MX in 2010 and won the title two years later.
Xolos finished second in the regular season and beat Toluca 4-1 on aggregate in the final to claim the Apertura 2012 championship. The Mexican side went on to reach the quarter-finals of the Copa Libertadores.
28. Trabzonspor
Trabzonspor are the most successful club in Turkey outside the big three from Istanbul, but the Burgundy Blues had to wait almost 40 years between their sixth and seventh league titles.
The 1983/84 champions finally added another title in 2021/22, finishing eight points ahead of Fenerbahce in a strange season which saw Besiktas come in sixth and Galatasaray down in 13th. Trabzonspor also won the Super Cup in June.
27. Wolfsburg
Wolfsburg won just three of their opening nine Bundesliga matches in 2008/09 and lost four times in their first 13 games in the competition.
But Felix Magath's men put together a remarkable run in the second half of the season, winning 14 of their last 16 matches to edge out Bayern Munich by two points and claim their first ever Bundesliga title.
26. Valencia
Up against Real Madrid's Galacticos and a new Barcelona project featuring Ronaldinho, Valencia were certainly not expected to win La Liga in 2003/04.
Champions in 2001/02 under Rafa Benitez, Los Che overtook a Madrid side in freefall towards the end of the campaign and stayed on top, finishing five points ahead of Barcelona and seven clear of Los Blancos in fourth. Valencia also won the UEFA Cup in one of the club's most memorable seasons.
25. Lens
Lens fans will never forget the 1997/98 season. In it, their team won Ligue 1 for the first time ever and reached two cup finals. And in the summer, their stadium hosted matches at the 1998 World Cup.
Lens won 10 of their last 12 matches to clinch the title and did so by just five goals from second-placed Metz. The Blood and Gold were beaten by Paris Saint-Germain in both domestic cup finals.
24. Leeds United
The last season of football before the Premier League saw Leeds United crowned champions. It was also the last time an English manager won the title in England.
Howard Wilkinson's side won 22 of their 42 games to beat Manchester United to the title by four points. The Whites followed up that success with a win in the Charity Shield, but their next season was disastrous as they failed to win away from home. Eric Cantona, the team's one shining light, was controversially sold to Manchester United in November and Leeds ended up finishing 17th.
23. Athletico Paranaense
Athletico Paranaense won promotion to Brazil's Serie A in 1995 and finished fourth in the regular season the following year, only to lose in the quarter-finals as the competition went to a knockout phase.
After finishing outside the play-off places in the next three campaigns, Athletico came second in the league phase in 2001, going on to beat Sao Caetano 5-2 on aggregate in the final. Since then, the red and blacks have won two Copas Sudamericana and have twice reached the final of the Copa Libertadores.
22. Sampdoria
Led from the front by Gianluca Vialli and Roberto Mancini, Sampdoria sealed a first ever Serie A title in 1990/91, beating AC Milan to the Scudetto by five points.
The Genoa outfit also finished as runners-up in the Coppa Italia and the following season, went all the way to the final of the European Cup, losing narrowly to Barcelona at Wembley.
21. Lille
Given Paris Saint-Germain's enormous wealth and array of world-class players, it takes something special for another club to win Ligue 1 these days. Lille produced exactly that in 2020/21.
With 24 wins and 11 draws, Lille pipped PSG to top spot by a single point to win their fourth Ligue 1 title and their first in exactly a decade.
20. Blackburn Rovers
Bankrolled by steelworks owner Jack Walker, Blackburn Rovers returned to English football's top flight in 1992 and after finishing as runners-up in 1994, went on to win the Premier League the following season.
With Kenny Dalglish as manager and a host of star signings, including Alan Shearer, Blackburn edged out Manchester United to win their first championship in over 80 years. Recent times, however, have been much more difficult.
19. AZ Alkmaar
After a difficult second spell at Barcelona, Louis van Gaal returned to his homeland to rebuild his reputation as he signed for AZ Alkmaar in 2005.
The Dutch coach, who finished his playing career with AZ, spent four seasons in charge of the Alkmaar club and surprisingly led the Cheese Farmers to the title in 2008/09. Sergio Romero and Mousa Dembele both featured in a talented team, which finished 11 points clear of FC Twente and 12 ahead of Ajax.
18. Deportivo Pereira
Deportivo Pereira came close to bankruptcy in 2014 but managed to stay afloat and after eight years in Colombia's second tier, the yellow and reds returned to the top flight in 2019.
After finishing fifth in the regular season, the team from the foothills of the Andes topped their group in the second phase and went on to beat Independiente Medellin on penalties in the final.
17. Nottingham Forest
Nottingham Forest appointed Brian Clough as manager in 1975 and would soon become one of the best teams both in England and in Europe.
Forest won their first and only league title in 1977/78, finishing seven points ahead of Liverpool. Although unable to repeat that triumph, the Reds went on to win the next two European Cups in a glorious era.
16. Gent
Gent finished the 2014/15 regular season in second place behind rivals Club Brugge in the Belgian Pro League, but came out on top in the championship play-off to win their first ever title.
The Buffalos' title followed three successive Anderlecht wins and they followed it up by beating Club Brugge in the Super Cup in July.
15. Alania Vladikavkaz
Alania Vladikavkaz shocked the Russian football world by winning the title in 1995 against all the odds, becoming the first league champions from outside Moscow.
A provincial club from the south of Russia, Vladikavkaz finished above five capital clubs (Lokomotiv, Spartak, Dynamo, Torpedo and CSKA Moscow) with 22 wins from their 30 games. The club later fell into decline and after a series of name changes, was dissolved. A new team, FC Alania Vladikavkaz, was created in 2019.
14. Rocha
Rocha were only founded in 1999 and in 2005, became the first Uruguayan club from the "interior" (inland) to win the national championship.
After edging out Nacional to claim the Apertura title, the team did their lap of honour with their mascot, a cow owned by journalist Robert Santurio. A year later, Rocha became the first Uruguayan club from outside Montevideo to feature in the Copa Libertadores, but later slipped down to the third tier.
13. Derby County
Brian Clough and Peter Taylor took over at Derby County in 1967, with the Rams 18th in the Second Division. Five years later, they won the First Division title.
Derby finished with 58 points, one ahead of Leeds, Liverpool and Manchester City. The following season, the Rams reached the semi-finals of the European Cup. Clough and Taylor left Derby in October 1973 after a fallout with chairman Sam Longson. Derby went on to win the title again under Dave Mackay in 1974/75.
12. Banfield
In Argentina, as in a number of other countries across Latin America, the league championship is split in two and played in two competitions of 19 games.
That gives the smaller sides a greater chance of success, but clubs like Banfield are still not expected to win. In the 2009 Apertura, the historic but humble outfit from Greater Buenos Aires claimed the title, despite defeat on the final day at Boca Juniors. Banfield's squad featured a young James Rodriguez.
11. Bursaspor
Bursaspor's Super Lig triumph in 2009/10 saw the Turkish title leave Istanbul for the first time since 1984 and has been described as the biggest shock in the history of the competition.
The Green Crocodiles finished a point ahead of Fenerbahce, with Galatasaray and Besiktas 10 further back. Previously, the Bursa-based team's only trophy was a Turkish Cup in 1985/86.
10. Napoli
Diego Maradona may have been the best player in the world in the mid-1980s, but winning the Scudetto seemed like a distant dream for Napoli.
No club from the south of Italy had ever won Serie A and in the Argentine's first season, the club had finished sixth and then third. But in 1986/87, Napoli won 15 of their 30 games to beat Juventus to the title by three points. History had been made and three years later, they did it again.
9. Rijeka
Between 2005 and 2023, Dinamo Zagreb won the Croatian championship 17 times out of a possible 18. The only other winner in that time was not their fierce rivals Hajduk Split, but HNK Rijeka.
Almost relegated in 2012, the club from the bustling port city punched above their weight to edge out Dinamo by two points in 2016/17 and win their first ever league title. Rijeka's stadium has a capacity of just over 8,000.
8. FC Twente
A year after AZ Alkmaar's surprise win in the Eredivisie, there was another shock in 2009/10 as FC Twente were crowned champions in the Netherlands.
Steve McClaren's side racked up an impressive 27 wins from their 34 matches to edge out Ajax by a single point and finished second behind the Amsterdam giants the following season under Michel Preud'homme.
7. Deportivo La Coruña
Deportivo La Coruña almost won La Liga in 1993/94, losing out on the final day due to their inferior head-to-head record with Barcelona after Miroslav Djukic missed a penalty in a 0-0 draw against Valencia.
But in 1999/2000, having finished 12th and sixth in the previous two seasons, the Galicians claimed the title by five points from Barcelona and Valencia – the two teams that had denied them in 1994 – with Real Madrid back in fifth.
6. Larissa
Only six clubs have won the Greek championship in its entire history, with Olympiacos, Panathinaikos and AEK Athens having claimed the large majority of titles.
Of the other winners, three-time champions Aris Thessaloniki last triumphed in 1946. Surprises, therefore, are few and far between. But in 1987/88, Athlitiki Enosi Larissa upset the status quo with a first ever title after winning 18 of their 30 games and edging out AEK by three points.
5. Boavista
Since the creation of the Portuguese league in 1934, all but a couple of the titles have been won by Benfica, Porto and Sporting CP. The other two were claimed by Belenenses in 1946/46 and Boavista in 2000/01.
Boavista led for the entire second half of the competition in their title triumph as the Porto-based club racked up 23 wins from 34 games and lost only three times, clinching it by a single point from their city rivals.
4. Kaiserslautern
Six years before leading Greece to victory at Euro 2004, Otto Rehhagel inspired another underdog success as Kaiserslautern clinched the Bundesliga title in 1997/98.
Kaiserslautern had been relegated in 1996 but won promotion the following season and beat Bayern Munich to the title by two points after winning 19 of their 34 games. Their squad featured a young Michael Ballack and a veteran Andreas Brehme in the final campaign of his career.
3. Montpellier
Taken over by Qatar Sports Investments in 2011, Paris Saint-Germain were expected to dominate French football fairly quickly. But they would have to wait.
Instead, Montpellier went on to top Ligue 1 in 2011/12, winning 25 of their 38 games to pip PSG to the title by three points. France striker Olivier Giroud was the star, with 21 goals in the league, and club president Louis Nicollin dyed his hair orange and blue in the club colours after making a promise to television channel TF1.
2. Leicester City
After a relegation battle in 2014/15, Leicester City were not expected to challenge towards the top end of the Premier League the following season – let alone win it.
The appointment of Claudio Ranieri as manager was questioned, but turned out to be a masterstroke as the Italian led the Foxes to the title against all odds ahead of Arsenal and Tottenham. The triumph had seemed so unlikely that former Leicester player and fan Gary Lineker vowed to present Match of the Day in his underpants if the Foxes won it – and he did.
1. Hellas Verona
They call it "the year of the miracle". In 1984/85, unfancied Hellas Verona shocked Serie A by claiming the Scudetto.
In a season which saw referees randomly assigned to avoid possible bribes, much of the focus has been on Diego Maradona at Napoli and Michel Platini at Juventus, but Osvaldo Bagnoli's side came through the pack with 15 wins and just two defeats to seal a historic triumph.
