|Lampard scored four to add to goals from Florent Malouda and Salomon Kalou [GALLO/GETTY]
Arsenal lost ground in the English Premier League title race as Kevin Phillips scored a late equaliser for Birmingham City while Chelsea crushed Aston Villa 7-1 and Manchester United won 4-0 at Bolton.
Frank Lampard scored four goals for Chelsea as they went three ahead of Arsenal who drew 1-1 after Phillips cancelled out Samir Nasri's opener.
Chelsea were briefly two points clear at the top of the table before United retook the lead when Dimitar Berbatov scored two goals at the Reebok Stadium after Jlloyd Samuel had bizarrely put through his own net. Darren Gibson added a fourth.
West Ham United hurtled further into relegation trouble with a 1-0 home defeat to Stoke City while Hull eased their own fears with a 2-0 win over Fulham.
Tottenham Hotspur beat Portsmouth 2-0 to cement their claim on the fourth European Champions League spot while Wolverhampton Wanderers secured a nil-nil draw with Everton at Molineux.
The victory at Stamford Bridge was Chelsea's biggest of the season, supplanting their 7-2 drubbing of Sunderland.
Saturday March 27
Birmingham 1-1 Arsenal
Chelsea 7-1 Aston Villa
Hull City 2-0 Fulham
Tottenham 2-0 Portsmouth
West Ham 0-1 Stoke City
Wolves 0-0 Everton
Bolton 0-4 Man Utd
Sunday March 28
Burnley v Blackburn
Liverpool v Sunderland
Monday March 29
Man City v Wigan Athletic
It also saw England midfielder Lampard take his tally for the season to 21 goals as he passed the 150 mark for the Blues.
And it meant Chelsea had scored 12 goals in a week after a 5-0 rout of basement club Portsmouth.
Lampard gave Chelsea a 15th minute lead when he struck at the far post following Florent Malouda's centre across the face of goal.
But Villa - who face holders Chelsea in next month's FA Cup semi-final - equalised in similar fashion when Norway striker John Carew turned in Ashley Young's cross in the 29th minute.
A minute before half-time Lampard restored Chelsea's lead with a fiercely struck penalty after James Collins tripped Yuri Zhirkov in the box.
Malouda then wrapped up the points when the France winger turned in a cross from Russia international Zhirkov three minutes before the hour mark.
And soon afterwards Lampard had the fifth hat-trick of his career when he scored his second penalty following a foul on Zhirkov by Richard Dunne.
Villa conceded another when Malouda scored his 13th of the season after being played in by Lampard.
Salomon Kalou made it 6-1 and there was still time for Lampard to score his fourth goal.
Spurs maintain grip
Tottenham maintained their grip on fourth place ahead of Villa, Manchester City and Liverpool as Portsmouth were put away by two former players and their former manager.
Striker Peter Crouch opened the scoring in the 27th minute when the England forward headed in Gareth Bale's cross past David James.
Spurs doubled their lead through another Pompey old boy in Niko Kranjcar, a member of the Portsmouth side that won the 2008 FA Cup under now Spurs boss Harry Redknapp, when the midfielder turned in fellow Croatian Luka Modric's deflected shot four minutes before the break.
Nasri's goal nine minutes from time appeared to have sealed victory for Arsenal as they challenge United and Chelsea at the top only for veteran striker Kevin Phillips to equalise in the closing seconds after a mistake by Gunners goalkeeper Manuel Almunia.
Gianfranco Zola witnessed his West Ham side's sixth straight loss, their worst run in the top flight for 43 years, leaving the Eastenders above the drop zone on goal difference from Hull, after a goal from Ricardo Fuller.
Hull's Jimmy Bullard scored against his old club from the penalty spot in the 16th minute after Jozy Altidore was brought down by Chris Smalling.
And the Tigers made it 2-0 three minutes after the break when Craig Fagan looped a header over Australia goalkeeper Mark Schwarzer.
Liverpool continue their increasingly Quixotic quest for fourth place at home to Sunderland on Sunday when relegation candidates Burnley face Blackburn in a Lancashire derby.
Manchester City host Wigan Athletic on Monday night.