Domestic leagues are often considered to be the hardest competition to win.
To claim the title, clubs must show strength, resilience and above all, consistency, across a long season. Occasional excellence or moments of brilliance are not enough.
If winning the league is difficult, securing a title without losing a match is an achievement reserved for truly special sides.
Over the years, a select group of clubs have completed Invincible seasons. Here, a look at some of the teams that went unbeaten in a league campaign...
16. Preston North End
Preston North End were the winners of the inaugural English League Championship in 1888/89 and the Lilywhites took the title without losing a game.
PNE racked up 18 wins and four draws in the 22-game season, with 74 goals scored and 15 conceded, to finish 11 points clear of second-placed Aston Villa. The original Invincibles.
15. Red Star Belgrade
Red Star Belgrade won the Serbian SuperLiga for a third season in a row in 2022/23 and the capital club did it in style with an unbeaten run to the title.
After 26 wins and four draws in the regular season, Crvena zvezda scored four more victories and another three ties in the championship round to finish with 97 points in a memorable campaign. Red Star also won the Serbian Cup without defeat, but were beaten in a Champions League play-off by Israeli side Maccabi Haifa and went on to lose four of their six Europa League group games.
14. Benfica
Benfica went into the 1972/73 season as back-to-back Portuguese champions and made it three in a row in a first-ever unbeaten league season.
The Lisbon giants won 28 of their games, twice as many as second-placed Belenenses, and drew the other two. Eusébio netted 40 goals in the league alone and 42 in all competitions. The Eagles were less successful in the knockout competitions, though, losing to Leixões in the Taça de Portugal and to Derby County in the European Cup. Benfica also went unbeaten in the league in the 1977/78 season, but lost out on goal difference to Porto.
13. Peñarol
Peñarol were not the first Uruguayan club to go through a league season unbeaten. That was their Montevideo rivals, Nacional, in 1917.
But the Yellow and Blacks have achieved the feat seven times since – in 1949, 1954, 1964, 1967, 1968, 1975 and 1978. The first five of those were 18-game seasons, with the latter two 22-match campaigns.
12. Beşiktaş
Beşiktaş became the first Turkish team to win the league without losing a single match, beating Istanbul rivals Galatasaray and Fenerbahçe to the title in 1991/92.
Under former England midfielder Gordon Milne, the Black Eagles won 23 games and drew seven to claim their 10th Turkish title and a third in a row. Beşiktaş also won the league in 1985/86, edging out Galatasaray on goal difference after their Istanbul rivals had gone undefeated in a 36-game season.
11. Steaua Bucharest
Steaua Bucharest are Romania's most successful side and the Red and Blues were particularly strong in the late 1980s, winning the European Cup in 1986 and reaching the final again in 1989.
Between 1984 and 1989, Steaua won five consecutive Romanian league titles. The last three of those – in 1986/87, 1987/88 and 1988/89 – were all achieved without losing a game and more impressive still, the capital club also won the Romanian Cup in each of the three campaigns.
10. Real Madrid
After the establishment of the Second Spanish Republic in April 1931, Real Madrid lost their "Real" title, as well as the royal crown from their crest, and went back to the name Madrid Football Club.
But Los Blancos enjoyed a special season in 1931/32. With the legendary Ricardo Zamora in goal, the capital club won their first ever La Liga title, finishing unbeaten in an 18-game campaign which featured 10 wins and eight draws – including a 2-2 tie away to fierce rivals Barcelona at Les Corts on the final day. Madrid also won the Campeonato Regional Centro, with just one defeat, but were beaten by Deportivo La Coruña over two legs in the last 16 of the Copa del Presidente de la República. Two seasons earlier, Athletic Club went unbeaten in La Liga across 18 games and also won the Copa del Rey.
9. PAOK Thessaloniki
Greek football has traditionally been dominated by clubs from Athens, but northern outfit PAOK Thessaloniki upset the status quo by winning a league and cup double in 2018/19.
PAOK beat Olympiacos to the title courtesy of 26 wins and four draws in an unbeaten season, conceding just 14 goals along the way, and added the Greek Cup thanks to a 1-0 victory over AEK Athens in the final. In the knockout competition, PAOK overcame first-leg defeats to Panachaiki and Panionios in the last 16 and the quarter-finals, respectively. Their European season was more difficult, though, with defeat to Benfica in a Champions League play-off and then five losses out of six in the Europa League group stages – two versus Chelsea and MOL Vidi, plus another against BATE Borisov.
8. Dynamo Kyiv
Managed by their former striker Serhiy Rebrov, Dynamo Kyiv secured a domestic double in 2014/15 without losing a single match.
Dynamo claimed the Ukrainian Premier League title, finishing 10 points ahead of Shakhtar Donetsk after 20 wins and six draws from their 26 games. The Blue and Whites also beat Shakhtar on penalties to win the Ukrainian Cup final. Rebrov's side did lose four games in Europe, though, eventually bowing out to Fiorentina in the Europa League last eight.
7. Celtic
Brendan Rodgers' first spell at Celtic began with a 1-0 defeat to Gibraltar's Lincoln Red Imps in a Champions League qualifier, but the Northern Irishman led the Hoops to the Scottish Premiership title without losing a game after 34 wins and four draws.
Celtic also went on to win the Scottish Cup and the Scottish League Cup to complete a domestic treble without defeat, but the Bhoys did lose twice to Barcelona and once to Borussia Mönchengladbach in the Champions League, finishing bottom of Group C.
6. AC Milan
AC Milan were a formidable force in the early 1990s and the Rossoneri won three Serie A titles in a row between 1992 and 1994.
The first of those came after an unbeaten season as Fabio Capello's side claimed the Scudetto with 22 wins and 12 draws. Milan had finished second the previous season, but were banned from participating in European competition after refusing to resume their 1990/91 European Cup quarter-final match away to Olympique Marseille. The club's only defeat in the 1991/92 campaign was a 1-0 loss to Juventus in the Coppa Italia semi-final second leg, following a 0-0 draw at San Siro.
5. Juventus
Having finished seventh in Serie A the previous season, Juventus won the first of nine straight Scudetto titles in 2011/12 – and the Bianconeri did not lose a single match.
Antonio Conte's side won 23 and drew 15 of their 38 games to take the title ahead of AC Milan by four points. Not playing in Europe due to their poor campaign in 2010/11, Juve also reached the Coppa Italia final, losing their only match of the campaign in a 2-0 defeat to Napoli at Rome's Stadio Olimpico.
4. Porto
Porto won four out of four trophies in an unprecedented 2010/11 campaign under André Villas Boas.
The Dragons cruised to the Primeira Liga title with 27 wins and three draws and beat Vitória de Guimarães to win the Taça de Portugal, having defeated the same side to claim the SuperTaça back in August. Porto's only two defeats of the season came in the Europa League – against Sevilla and Villarreal – but neither mattered as Villas Boas' side came through both ties and beat Braga in the final to cap a remarkable season. Two seasons later, Porto went unbeaten again in the league, with Vitor Pereira's side finishing with 24 wins and six draws to edge out Benfica by a single point.
3. Arsenal
Arsenal won the Premier League title in 2003/04 with 90 points, finishing 11 clear of second-placed Chelsea after 26 wins and 12 draws.
That team, managed by Arsène Wenger, became known as The Invincibles and received a special gold trophy for the achievement of completing the Premier League season unbeaten. The Gunners did lose six games in other competitions, though – against Dynamo Kyiv, Inter and Chelsea in the Champions League; home and away to Middlesbrough in the League Cup semi-finals; and versus Manchester United in the FA Cup.
2. Bayer Leverkusen
Bayer Leverkusen had never won the Bundesliga, but the German club changed that in a remarkable 2023/24 campaign.
Xabi Alonso's side ended 11 years of Bayern Munich dominance by winning the Bundesliga and the Black and Reds claimed the title without losing a single game, with 28 wins and six draws. Leverkusen also won the DFB-Pokal with six successive victories and went within a game of not losing at all, eventually going down 3-0 to Atalanta in the Europa League final in Dublin – their sole defeat in 53 competitive matches.
1. Ajax
Ajax won 27 of their 34 Eredivisie games in 1994/95 and drew the other seven, scoring 106 goals and conceding 38.
Louis van Gaal's side also won the Champions League without losing a game, beating AC Milan in the final, and thrashed Feyenoord 3-0 in the Dutch Supercup. In fact, the Amsterdam club lost only one match in the entire season as they were beaten 2-1 by Feyenoord in the quarter-finals of the Dutch Cup – and even that defeat came in extra time.
