The 2003–04 season was Arsenal Football Club's 12th season in the Premier League and their 78th consecutive season in the top flight of English football. It began on 1 July 2003 and concluded on 30 June 2004, with competitive matches played between August and May. The club ended the Premier League campaign as champions without a single defeat – a record of 26 wins and 12 draws. Arsenal fared less well in the cups, eliminated in the FA Cup and League Cup semi-finals to Manchester United and Middlesbrough respectively, and at the quarter-final stage of the UEFA Champions League to Chelsea.
The main addition to the first team was goalkeeper Jens Lehmann for £1.5 million; striker José Antonio Reyes was later purchased in the winter transfer window. Arsenal retained their best players and successfully negotiated new contracts for captain Patrick Vieira and midfielder Robert Pires. The stability of the squad meant Arsenal were considered front-runners for the Premier League title, along with Manchester United, and Chelsea who were taken over by Russian billionaire Roman Abramovich.
A strong start to the season saw Arsenal top the league table after four matches. The team's draw at Manchester United in September marked an unsavoury episode between both clubs: several Arsenal players were charged and fined accordingly by The Football Association for their part in a mass brawl that occurred after the match. In November, Arsenal beat Dynamo Kyiv by a single goal and more impressively scored five against Inter Milan at the San Siro – two results which kick-started their Champions League campaign. At the turn of the year, the team won nine league matches in a row to consolidate first position. In the first week of April, they were eliminated from the FA Cup and Champions League, but by the end of the month had secured their status as league champions, with a 2–2 draw against local rivals Tottenham Hotspur.
34 different players represented the club in five competitions and there were 15 different goalscorers. Arsenal's top goalscorer for the third year running was Thierry Henry, who scored 39 goals in 51 games. The Frenchman was given the accolade of PFA Players' Player of the Year by his fellow peers and the FWA Footballer of the Year by football writers. Although the Arsenal team were unsuccessful in cup competitions, their dominance in the league was regarded by many commentators as a standalone achievement. They acquired the nickname "The Invincibles", much like the Preston North End team that went unbeaten in the inaugural Football League season. The club was awarded a golden replica trophy by the Premier League once the season concluded and they remained unbeaten for 49 games, setting a new record. In 2012, the Arsenal team of 2003–04 won the "Best Team" category in the Premier League 20 Seasons Awards.
Background
Arsenal had finished the previous season as runners-up in the Premier League, overhauled by Manchester United in the final ten weeks of the season. The club did, however, retain the FA Cup, with a 1–0 win against Southampton. Such was Arsenal's effective start to the 2002–03 campaign, manager Arsène Wenger suggested his team could remain the whole season undefeated in all competitions:It's not impossible as A.C. Milan once did it but I can't see why it's so shocking to say it. Do you think Manchester United, Liverpool or Chelsea don't dream that as well? They're exactly the same. They just don't say it because they're scared to look ridiculous, but nobody is ridiculous in this job as we know anything can happen. The team lost to Everton a month after Wenger's proclamation; teenager Wayne Rooney scored the match winner, which ended a run of 30 league games without defeat. By February 2003, Arsenal moved five points clear of Manchester United at the top of the league table, but injuries to key players, not least captain Patrick Vieira, had destabilised the team. Draws in April, coupled with a defeat to Leeds United at home, mathematically ended Arsenal's chances of retaining the title. Wenger refuted opinions from the media that their season was a failure and said:
In the close season, Chelsea was sold to Russian billionaire Roman Abramovich for £140 million, the biggest takeover in British football history at the time. Arsenal vice-chairman David Dein however was displeased, and quipped that Abramovich had "parked his Russian tanks on our lawn and is firing £50 notes at us", Abramovich was said to have placed a bid for Arsenal striker Thierry Henry, which was turned down at once.