Manchester United's defensive troubles have allowed Arsenal to establish a five-point lead at the top of the Barclaycard Premiership after Middlesbrough won 3-2 at Old Trafford.
United, who have now conceded eight goals in the last three games, fought back from going two goals down following Juninho's first-half double but were beaten by Joseph-Desire Job's late strike.
Juninho put Boro in front 11 minutes before the interval when he reacted fastest to nod home the loose ball after Franck Queudrue's speculative effort crashed on to the bar from Tim Howard. Then, on Boro's next attack, the Brazilian was left with enough space to guide Stewart Downing's cross into the net.
Ruud van Nistelrooy halved the deficit when he lashed home his 102nd United goal after Louis Saha had chested Ryan Giggs' cross into his path shortly before the break. And the Dutchman's flick from Phil Neville's cross allowed Ryan Giggs to equalise at the second attempt.
But United were rocked when Job hit a late winner for Boro after Doriva set him up on the edge of the box.
Chelsea, in third place, moved to within a point of United thanks a comfortable 2-0 win at struggling Portsmouth. Scott Parker scored his first goal following his £10million move from Charlton when he lashed home on the volley after exchanging passes with Adrian Mutu to give Chelsea the lead.
Hernan Crespo was booked for diving when he should have been awarded a penalty shortly after coming on midway through the second half, but the Argentinian took revenge when he chested in Chelsea's second goal after Jimmy Floyd Hasselbaink had hit the bar.
Manchester City have still not won a Premiership game since November 1 after going down 2-1 at Liverpool. Michael Owen broke his scoring drought, which had stretched back to October, as the home side surged into a third-minute lead.
The England striker slipped the ball home after being put through by Dietmar Hamann. Shaun Wright-Phillips finished following a cross from Anfield old boy Steve McManaman to equalise but the home side regained the lead almost immediately through Steven Gerrard and, despite some spirited City attacking, held on for victory.
Jermain Defoe made it two goals from two appearances for Tottenham in the 4-2 win at troubled Charlton. Simon Davies opening the scoring for Spurs when he took advantage of Paul Konchesky's misplaced header back to his keeper.
And Defoe found the net in slightly fortuitous fashion when Kasey Keller saved his initial effort but the ball bounced off his head and into the net. Ledley King made it 3-0 before Graham Stuart pulled one back for the home side. Spurs, who famously threw away a three-goal lead to lose 4-3 to Manchester City in the FA Cup last week, were wobbling when Chris Perry reduced the arrears further with nine minutes remaining.
However Johnnie Jackson's late strike ensured Tottenham did not collapse and sentenced the Addicks to a third consecutive defeat.
Another striker to continue his good start at a new club was Blackburn's Jon Stead who scored his second goal in as many games in the 1-1 draw with Newcastle at Ewood Park. Craig Bellamy scored on his first start since a lengthy injury lay-off but Stead upstaged his more expensive team-mates when he grabbed the equaliser.
Birmingham cruised to a comfortable 3-0 home win over Everton. Damien Johnson fired them into the lead following Robbie Savage's free-kick and Stan Lazaridis doubled their advantage with a fine solo effort. Mikael Forssell supplied a smart finish for the third.
City rivals Aston Villa won 2-1 at Fulham, who had American defender Carlos Bocanegra sent off for a terrible challenge on Mark Delaney. Luis Boa Morte opened the scoring inside the first minute at Loftus Road but Villa were level when Fulham keeper Edwin van der Sar failed to clear Juan Pablo Angel's shot and the Colombian followed up to score.
Darius Vassell put the visitors in front in the 32nd minute when he headed home Thomas Hitzlsperger's corner and Villa held on for a valuable away win.