Manchester United took advantage of a further slip up from Arsenal to move to the top of the table on a dramatic weekend of Premier League action.
United were made to work unexpectedly hard by Championship-bound Derby County before overcoming the league's bottom club 1-0 at Pride Park.
Meanwhile, Arsenal salvaged a late point after a 1-1 draw at home to Middlesbrough, but it was not enough to prevent the champions from moving above them on goal difference.
Sir Alex Ferguson's side also have a game in hand on the Gunners after Cristiano Ronaldo's 31st goal of the season in all competitions shot down a brave Rams outfit.
Former Arsenal striker Jeremie Aliadiere had put Boro in front at the Emirates Stadium, before Kolo Toure's 86th minute equaliser.
Boro striker Mido was sent off in the latter stages of the match for violent conduct after catching Arsenal full-back Gael Clichy with a high boot.
Elsewhere, Chelsea moved to within three points of Arsenal after John Terry's tenth minute header edged out Sunderland 1-0 at the Stadium of Light.
Liverpool also kept up the pressure on the top three after coming from behind to beat Reading 2-1 at Anfield.
Javier Mascherano's first goal for the club and another strike from hot-shot Fernando Torres secured a fifth successive league win for Rafael Benitez's side.
The Reds are also now firm favourites to claim fourth place in the league and the final Champions League spot after main challengers Everton suffered a surprise defeat on Sunday.
David Moyes' side followed up their midweek UEFA Cup exit on penalties to Fiorentina with a 1-0 defeat at lowly Fulham.
Brian McBride's winner left the Toffees three points adrift of their Merseyside rivals, but also boosted Fulham's outside hopes of avoiding the drop.
On Saturday, Portsmouth moved above Aston Villa into sixth spot after a 2-0 victory over the Midlands club at Fratton Park.
Jermain Defoe and a freak own goal from Nigel Reo-Coker secured the points for the FA Cup semi-finalists, who had Sulley Muntari sent off late on for two yellow cards.
Villa, whose own UEFA Cup hopes suffered a potentially fatal blow with the defeat, were also reduced to ten men following the second-half dismissal of Olof Mellberg.
West Ham eased the pressure on under-fire manager Alan Curbishley as they ended a streak of three successive 4-0 defeats with a 2-1 win over Blackburn Rovers.
Teenage debutant Freddie Sears came off the bench at Upton Park to grab an 81st minute winner with a goal on a memorable senior debut.
Elsewhere on Sunday, Bolton remain deep in relegation danger after Emile Heskey's first goal for seven months condemned Gary Megson's strugglers to a 1-0 defeat at local rivals Wigan Athletic.
The Latics, who had Jason Koumas sent off in the fifth minute at the JJB Stadium, boosted their own survival chances after moving up to 12th in the table with the precious three-point haul.
Meanwhile, Manchester City kept their outside chances of UEFA Cup qualification alive after moving up to eighth in the table on the back of a 2-1 win over Tottenham.
Spurs had taken a first-half lead through Robbie Keane, but City responded to take the points courtesy of strikes from Stephen Ireland and Nedum Onuoha.