The Merseysiders battled back from a goal down to defeat the league leaders in clinical fashion.

Cristiano Ronaldo opened the scoring from the penalty spot but Fernando Torres and Steven Gerrard gave Liverpool the lead before the break, with Fabio Aurelio and Andrea Dossena easing the visitors well clear before the end.

It was an day to forget for Nemanja Vidic, who gifted Torres the equaliser before being sent off against Liverpool for the second time this season as Rafael Benitez's side reduced United's lead at the top to four points, albeit having played a game more.

It represented Liverpool's biggest win at United since 1936 and could yet trigger an amazing championship revival.

With Aston Villa playing on Monday morning, Arsenal took the opportunity to move above Martin O'Neill's side into fourth with a 4-0 win at home over Blackburn.

Andrey Arshavin scored his first goals for the club since his drawn-out transfer from Zenit St Petersburg in January, meeting Theo Walcott's cross in the second minute to put the Gunners in front.

The Russian then turned on the flair for his second on 65 minutes, receiving the ball wide on the left, dummying inside Danny Simpson and faking a cross before hammering the ball past Paul Robinson from close range.

Emmanuel Eboue's two late strikes - the second a penalty - put the gloss a victory which takes the Gunners above Villa on goal difference, having played a game more.

Everton also kept up the pressure in the race for a Champions League spot, battling to a 3-1 win over relegation-threatened Stoke at Goodison Park.

Brazilian striker Jo, another transfer-window acquisition, put the Toffees ahead on 18 minutes after playing a one-two with Marouane Fellaini and Joleon Lescott doubled their lead six minutes later, tapping the ball in from close range after Thomas Sorensen had fumbled Tim Cahill's header.

Stoke pulled a goal back against the run of play five minutes into the second half, Ryan Shawcross's header across Tim Howard making it 2-1, but Fellaini killed them off with Everton's third in added time.

Tony Pulis' side now find themselves rooted in the bottom three in 18th position.

They replace Portsmouth, who looked set for victory over second-bottom Middlesbrough thanks to Peter Crouch's volleyed strike on the half-hour.

Gareth Southgate's problems were compounded when Matthew Bates was sent off for a needless second yellow card, booked for diving with 15 minutes to go.

But Marlon King scored a dramatic equaliser for Boro in injury time to secure his team a vital point.

Pompey move up to 17th, clear of the drop zone on goal difference, while Boro stay in 19th, two points from safety.

In another vital clash at the bottom of the table, it finished all-square at the KC Stadium, Geovanni's ninth-minute header putting Hull one-up against Newcastle only for Steven Taylor to level things with a composed strike on 38 minutes, converting Nicky Butt's cross to make it 1-1.

It was a result neither side really wanted, Hull moving up to 12th but still only four points above the relegation places, while Newcastle remain even more in the mire, up one place to 16th but afloat of the bottom three on goal difference alone.

Sunderland are only three points clear of the drop zone after losing 2-1  to Wigan at the Stadium of Light.

Ben Watson gave Steve Bruce's side the lead with a strike from 30 yards on 12 minutes before the Black Cats equalised through a scrappy Grant Leadbitter goal in the 41st minute.

But former Newcastle midfielder Charles N'Zogbia left Sunderland fans sick with the winner four minutes later, slotting the ball under Martin Fulop after a superb run through the home defence.

Elsewhere, Fulham moved up to ninth with a 3-1 victory at Bolton. Andy Johnson gave the visitors the lead three minutes before the interval only for Kevin Davies to pull one back for the Trotters in first-half injury time.

Fulham regained the lead on 56 minutes through Simon Davies, who converted a low volley after the ball had rebounded off the crossbar to him from a shot by Danny Murphy and substitute Diomansy Kamara wrapped up the points with Fulham's third two minutes before the final whistle.