Chelsea battered 10-man Newcastle United 5-0 at Stamford Bridge while United were 2-1 winners at local rivals Liverpool, with Ryan Giggs scoring twice.
Arsenal, who beat Tottenham Hotspur 2-1 in the north London derby on Saturday, still lead the table with 30 points. Chelsea have 29 and United 28.
Fourth-placed Charlton Athletic are seven points adrift of United in what is already a three-way tussle for the title with less than one third of the season gone.
Chelsea, 4-0 Champions League winners at Lazio on Tuesday, were again in scintillating form against a Newcastle side missing striker Alan Shearer due to illness at Stamford Bridge.
Claudio Ranieri's expensive team went in front when full back Glen Johnson, sent off against Lazio, slammed home Wayne Bridge's cross.
Argentine striker Hernan Crespo's sharp finish made it 2-0 and Newcastle were finished off before halftime when Frank Lampard cracked in a penalty conceded by Andy O'Brien, who fouled Adrian Mutu and was red-carded.
Damien Duff, with a thumping fourth, and Eidur Gudjohnsen, with a header, applied the coups de grace in the final quarter of a one-sided game.
"The lads did great at Lazio and a lot of people might have expected us to slip up after that but we proved today we are here to stay now," Lampard told Sky Sports television.
At Anfield Liverpool were dealt a blow before kickoff by the withdrawal of striker Michael Owen due to his ankle problem which will also keep him out of England's friendly against Denmark next Sunday.
A tight match opened up with a freak goal after 59 minutes by Giggs who curved in a free kick which just evaded the head of Ruud van Nistelrooy and Liverpool keeper Jerzy Dudek who was out of position.
It was not as bad an error as 11 months ago when Dudek allowed a headed back pass to go through his legs, presenting Diego Forlan with the first of his two goals in another 2-1 United win.
But Dudek really should also have prevented Giggs's angled shot from making it 2-0 soon after.
Liverpool finished strongly, with Kewell volleying home Florent Sinama-Pongolle's cross and but for two last-ditch tackles by United defenders and an untimely slip by Emile Heskey, they might have earned a point.
"We were more than hanging on. It was a nail-biting finish," said United manager Alex Ferguson who is on the verge of agreeing a contract extension.
In Sunday's other match Leicester City moved out of the relegation zone with their impressive 3-0 win at Manchester City. Jordan Stewart, Paul Dickov and Marcus Bent scored their goals.