The 2005–06 season was Manchester United's 14th season in the Premier League, and their 31st consecutive season in the top division of English football.

After having finished in third place in both of the previous two seasons, the Red Devils improved slightly to finish the 2005–06 season in second place, despite finishing 8 points off the lead.

However, despite the improvement in their league form, United's European form took a massive blow, with the club failing to reach the knockout stage of the UEFA Champions League for the first time since 1994–95. The club fared better in the FA Cup, reaching the Fifth Round, but their real success came in the League Cup, in which they beat Wigan Athletic 4–0 in the final. United became the first club in Premier League history to score 1,000 goals, a milestone reached on 29 October in the 4–1 defeat to Middlesbrough at the Riverside, with Cristiano Ronaldo scoring the goal.

The 2005–06 season also saw the departure of club captain Roy Keane, who had been at Old Trafford since 1993. Keane played his last game for the club on 18 September 2005 in a goalless draw with Liverpool, but was forced to withdraw from the match only a couple of minutes before full-time. It was later revealed that Keane had picked up a foot injury and he eventually left the club for his boyhood team Celtic on 18 November 2005. Keane was subsequently replaced as captain by his deputy, Gary Neville. On 25 November 2005, just seven days after Keane left the club, United fans were plunged into mourning by the death of legendary former player George Best, who died at age 59.

Pre-season and friendlies Manchester United began their pre-season in July 2005 with a 5–1 thrashing away to Clyde. The only goal of the first half was scored by United's Kléberson. In the second half, United fielded a completely different side. Paul Scholes opened the scoring in the second half, before Ruud van Nistelrooy added on United's third with a penalty. Neil McGregor pulled a goal back for Clyde when he struck home Steven Masterton's corner, but Liam Miller restored the three-goal margin after taking a short pass from Van Nistelrooy, and Van Nistelrooy finished the scoring in the 85th minute.

United then travelled down to England to face Peterborough United for Barry Fry's testimonial. The Posh held United to a 0–0 draw in the first half, but a Ruud van Nistelrooy hat-trick, a Cristiano Ronaldo brace, and a Giuseppe Rossi strike saw United win 6–0.

United then set out to East Asia for their 2005–06 pre-season tour. They started their tour of East Asia with a 2–0 win over a Hong Kong XI side, with the goals coming from Giuseppe Rossi and Dong Fangzhuo (his first goal for Manchester United). This was followed up with a 3–0 win over Beijing Hyundai, with Paul Scholes scoring a brace and Park Ji-Sung scoring his first goal for the Red Devils. United then travelled to Japan to face Kashima Antlers, a game in which they lost 2–1. Masashi Motoyama opened the scoring when he controlled a cross-field pass with his first touch and with his second lashed a superb volley over 'keeper Tim Howard into the far corner. United responded when Louis Saha threaded a pass to Cristiano Ronaldo who darted into the area before rolling the ball across the face of goal for Ryan Giggs to tap in. However, before half-time, Antlers restored their lead when Mitsuo Ogasawara's canny flicked pass gave Motoyama the space to fire in a powerful angled volley from eight yards.

United's pre-season tour of East Asia ended with a 2–0 victory over Urawa Red Diamonds. Wayne Rooney scored both goals, which were his first of United's Far East tour. Rooney got first after just five minutes when he threaded a low shot under Ryota Tsuzuki. Rooney's second was scored soon after when he dribbled past three players before lofting a delicate chip over Tsuzuki from the edge of the area.

Following their return to Europe, Manchester United rounded off their pre-season schedule with a 6–1 drubbing of their feeder club in Belgium, Royal Antwerp. Ruud van Nistelrooy grabbed a hat-trick, with United's other goals being scored by Paul Scholes, Cristiano Ronaldo, and Darren Fletcher.

United played one more friendly during the 2005–06 season, the final one being a home fixture against Celtic on 9 May. The game was played as a testimonial for former United captain Roy Keane, who left United as captain in November 2005. Keane played the first half in a Celtic shirt, and switched sides at half-time to play as his former role of United captain. United won 1–0, thanks to Cristiano Ronaldo's 55th-minute goal.

DateOpponentsH / AResultF–AScorersAttendance16 July 2005ClydeA5–1Kléberson 30', Scholes 48', Van Nistelrooy (2) 58' (pen.), 85', Miller 78'8,00020 July 2005Peterborough UnitedA6–0Van Nistelrooy (3) 54', 77', 84', Ronaldo 69', 90', Rossi 81'15,46023 July 2005Hong Kong XIA2–0Rossi 69', Dong 73'33,97126 July 2005Beijing HyundaiA3–0Scholes (2) 40', 43', Park 48'24,22428 July 2005Kashima AntlersN1–2Giggs 7'33,97130 July 2005Urawa Red DiamondsA2–0Rooney (2) 50', 65'58,3893 August 2005Royal AntwerpA6–1Van Nistelrooy (3) 12', 27' (pen.), 45', Scholes 15', Ronaldo 32', Fletcher 60'12,0009 May 2006CelticH1–0Ronaldo 55'69,591

FA Premier League

Manchester United started their Premier League season with a 2–0 win over Everton at Goodison Park. Ruud van Nistelrooy went close twice as the visitors dominated for long spells before the Dutch striker slotted in John O'Shea's cross two minutes before the interval. Wayne Rooney doubled United's lead 27 seconds in the second half after Joseph Yobo had ludicrously rolled the ball across the penalty area into his path. Marcus Bent's deflected volley struck the bar but Everton were disappointing. The hosts continued with the five-man midfield which served them so well in the 2004–05 season, though James Beattie only lasted 20 minutes before injury forced him off and Bent on.

United's next game in the FA Premier League was a home game against Aston Villa. Thomas Sørensen made a brilliant save to deflect a shot from Park Ji-Sung against the crossbar, while a Wayne Rooney volley was cleared off the line. Park missed a good chance after exchanging passes with Rooney before Sørensen saved headers from both Gabriel Heinze and Cristiano Ronaldo. Van Nistelrooy eventually scored the only goal of the game when he tapped home from Ronaldo's cross.

United continued their perfect start to the season with 2–0 away win at Newcastle United. Wayne Rooney opened the scoring in the 66th minute after pouncing on Jean-Alain Boumsong's error. Albert Luque thought that he had scored on his Newcastle debut, but his goal was ruled out for offside. Ruud van Nistelrooy glanced a header wide and had a penalty appeal turned down before sealing the victory with a low shot in injury time.

United's 100% all-win start to the season ended as they were held to a 1–1 home draw by their crosstown rivals Manchester City. Ruud van Nistelrooy gave United the lead in first-half injury time, turning home from close range after David James had saved his first effort brilliantly. United failed to take advantage of their supremacy, with van Nistelrooy and Park Ji-sung missing chances, and Joey Barton struck after 75 minutes, turning home Darius Vassell's effort.

Despite a second successive draw, this time away to Liverpool, United went up to third place in the FA Premier League table. Steven Gerrard saw a long free-kick bounce just wide in the first half, while Ruud van Nistelrooy went close for United with a chip over the bar. Liverpool continued to push after the break, with Gerrard heading over and Edwin van der Sar saving his drive, but United held firm.

After losing their all-win 100% start to the season, United's unbeaten record went too, with a shock 2–1 home loss to Blackburn Rovers. Morten Gamst Pedersen gave Blackburn a first-half lead as his free-kick drifted straight into the net. Ruud van Nistelrooy levelled for United when Wayne Rooney's shot proved too hot for Blackburn keeper Brad Friedel, but an error by Paul Scholes gifted the ball to Michael Gray, who set up Pedersen to slam home the winner.

United returned to winning ways with a 3–2 win over Fulham at Craven Cottage on 1 October 2005. Collins John put Fulham ahead, but Ruud van Nistelrooy equalised from the spot after Moritz Volz fouled Park Ji-Sung. Park then released Wayne Rooney to put United ahead after 18 minutes, only for Claus Jensen to level from a free-kick. van Nistelrooy completed the scoring in first-half injury time, sweeping home unmarked from another Park pass.

United's next game was an away game to Sunderland on 15 October. The Red Devils, wearing their blue away kit, won 3–1, pushing the Black Cats back into the relegation zone. A blistering break culminated in Wayne Rooney eluding Kelvin Davis and sliding the ball home for United's opener. Rooney played in Ruud van Nistelrooy for the Dutch striker to double the lead before a long-range strike from Stephen Elliott pulled a goal back. Anthony Le Tallec then went close to equalising before Giuseppe Rossi scored his first, and what turned out to be his only, league goal for Manchester United from 20 yards.

United dropped from 3rd to 5th in the FA Premier League table with a 1–1 home draw against Tottenham Hotspur on 22 October. Spurs were trailing 1–0 when Jermaine Jenas curled home a stunning free kick after Rio Ferdinand had fouled Jermain Defoe. That saved the blushes of England goalkeeper Paul Robinson, who had spilled Ruud van Nistelrooy's header to allow Mikaël Silvestre to touch home. Alan Smith, Cristiano Ronaldo and van Nistelrooy came close for United, but Spurs deserved their point. Spurs had three penalty appeals turned down in the match, two of which were decent shouts.

A 4–1 away loss to Middlesbrough pushed United down a further two places in the table. Edwin van der Sar gifted Middlesbrough the lead when he let Gaizka Mendieta's shot slip through his fingers. A mistake by Rio Ferdinand let in Jimmy Floyd Hasselbaink for the second, and Yakubu made it 3–0 from the spot after Stuart Parnaby was fouled. Yakubu set up Mendieta to make it 4–0. Cristiano Ronaldo headed home a consolation goal deep in injury time for the Reds - United's 1000th goal in the FA Premier League - but by then the home fans had long been celebrating a famous victory.

After the disastrous 4–1 loss to Middlesbrough, United opened November with a 1–0 victory over Chelsea, ending the defending champions' 40-match unbeaten run in the FA Premier League. Darren Fletcher scored the only goal of the game just over half an hour into the match with a header. The Scotsman appeared to be trying to head the ball back across the goal, but his effort looped inside the far post. Early in the second half, Ruud van Nistelrooy should have made the game safe, but he blazed his shot over. His miss meant United had to live on their nerves as Chelsea desperately sought the equaliser and Edwin van der Sar bravely denied Frank Lampard.

After the win against Chelsea, United won their next three FA Premier League games, with 3–1 and 2–1 away wins over Charlton Athletic and West Ham United and a 3–0 home victory over Portsmouth. Their winning streak was finally halted by Everton, who held United to a 1–1 draw at Old Trafford. Both goals were scored in the opening 15 minutes: James McFadden opened the scoring for Everton with just seven minutes played, with the Scottish forward beating Edwin van der Sar from a tight angle for the opening goal. Ryan Giggs guided the ball past Richard Wright to equalise after collecting a superb pass from Paul Scholes. Wright later saved from Alan Smith, Wayne Rooney, Gary Neville, Scholes and Giggs, and van der Sar denied McFadden as Everton hit back on the break.