Manchester United's Javier Hernandez (C) celebrates after scoring during their English Premier League soccer match against Stoke City at Old Trafford in Manchester, northern England, Jan 31, 2012. [Photo/Agencies]

Ex-Manchester United midfielder Darron Gibson did his old club a huge favour by scoring the winner for Everton in a 1-0 victory over Premier League leaders Manchester City, while United moved level on points at the top after beating Stoke City 2-0.

Ireland midfielder Gibson left United to move to Goodison Park earlier this month and his fierce strike on the hour, which took a slight deflection, proved decisive.

United, who trail their rivals on goal difference, eased past Stoke thanks to two penalties at Old Trafford from Javier Hernandez and Dimitar Berbatov.

City and United have 54 points from 23 matches, five ahead of Tottenham Hotspur who thumped Wigan Athletic 3-1 at White Hart Lane.

Dejected City manager Roberto Mancini said he had underestimated mid-table Everton.

"Probably, probably, probably," the Italian said in an interview with Sky Sports after he was asked if he had taken Everton too lightly.

"Maybe it's my fault because I prepared, maybe, bad for this game ... It is very important that we win our next game against Fulham."

The leaders enjoyed plenty of possession but created few openings to trouble a resolute home defence.

Everton, who paraded new signing Nikica Jelavic at halftime after the Croatia striker's move from Rangers, almost broke through early on but Joleon Lescott was well positioned on the goalline to clear Denis Stracqualursi's close-range header.

City went closest to an equalizer when midfielder Samir Nasri rattled the crossbar with a swerving 30-metre piledriver on 36 minutes.

United had no problems overcoming Stoke despite handing a first league start to goalkeeper Ben Amos, called up due to David de Gea being ill and Anders Lindegaard injured.

With Wayne Rooney still out with an ankle injury, Ferguson partnered Berbatov alongside Javier Hernandez up front and both made no mistake from the spot.

Mexico striker Hernandez fired home on 38 minutes after Jermaine Pennant had felled Park Ji-sung.

United were awarded a second penalty eight minutes after halftime and this time Berbatov scored after Antonio Valencia was brought down.