Premier League round-up: Cristiano Ronaldo's 22nd Premier League goal of the season helped Manchester United claim a 1-0 win over Derby which lifted them to the top of the table.
The Portugal winger latched on to a pass from Wayne Rooney and his low shot squirmed past Derby goalkeeper Roy Carroll from the left edge of the penalty area.
Paul Jewell's side had frustrated the champions for large periods of the game and United goalkeeper Ben Foster had produced a spectacular save from Rams striker Kenny Miller moments before half-time.
But Ronaldo eventually broke the deadlock in the 76th minute which ensured Alex Ferguson's side move a point clear of Arsenal who face Middlesbrough at the Emirates Stadium in the day's late kick-off.
John Terry gave Chelsea a 1-0 victory over Sunderland as Avram Grant's side kept the pressure up on the top two. Frank Lampard delivered a dangerous inswinging corner from the left which was met by the Chelsea captain in the 10th minute at the Stadium of Light.
Terry directed a downward header through a crowd of players and past Black Cats goalkeeper Craig Gordon.
Fernando Torres' 20th Barclays Premier League goal of the season helped Liverpool consolidate fourth place in the table with a 2-1 win over Reading.
Reading midfielder Marek Matejovsky broke the deadlock in the fifth minute at Anfield when he lashed a half-volley past a static Jose Reina and into the top-left corner of the net.
Javier Mascherano equalised in equally spectacular fashion in the 19th minute with his first goal in a Liverpool shirt with a powerfully-struck shot from the edge of the penalty area. Torres made the points safe when he headed a Steven Gerrard free-kick past goalkeeper Marcus Hahnemann from close range three minutes after the break.
An 11th-minute strike from Jermain Defoe and a Nigel Reo-Coker own-goal gave Portsmouth a 2-0 win over Aston Villa at Fratton Park. Defoe controlled a long ball from Glen Johnson before he deftly lobbed the ball over Villa goalkeeper Scott Carson from the right edge of the penalty area.
Reo-Coker scored Pompey's second after he directed the ball past Carson from 30 yards out in the 38th minute. Portsmouth midfielder Sulley Muntari and Aston Villa's Olof Mellberg were both sent off late in the game.
Fred Sears headed a dramatic winner nine minutes from time on his debut to give West Ham a 2-1 victory over Blackburn at Upton Park. Blackburn striker Roque Santa Cruz gave Mark Hughes' side the lead in the 19th minute when he glanced a header from a Morten Gamst Pedersen cross past Robert Green.
Dean Ashton equalised in the 39th minute after he spun away from the Blackburn defence on the edge of the area before he chipped the ball over Brad Friedel. Striker Sears replaced Nolberto Solano in the 75th minute and six minutes later saw his shot from 12 yards out saved by Friedel but was able to nod the rebound home.