Chelsea fight back to beat United
United had deservedly led through Wayne Rooney's 29th-minute strike but Chelsea's Brazilian defender David Luiz equalised nine minutes into the second half with his first goal for the club since joining from Benfica in the January transfer window.
The champions, unbeaten at home against United since 2002, then surged forward and secured all three points when Chris Smalling tripped substitute Yuri Zhirkov and Lampard fired home a penalty United manager Sir Alex Ferguson described as "soft".
United remain top of the Premier League with 60 points, four clear of Arsenal but with the London side now having a game in hand. Manchester City are third on 50 with champions Chelsea up to fourth on 48.
"It was a great performance by us. We didn't deserve that," Ferguson told Sky Sports. "It's three years in a row the referees' decisions have changed the game [between Chelsea and Manchester United at Stamford Bridge].
"I'm proud of my players tonight, they've endured a lot of decisions against them and they've done their best."
Defender Nemanja Vidic's stoppage-time red card for a second booking completed United's miserable night and the Serbian defender will miss Sunday's trip to Anfield.
Ferguson felt Luiz should also been sent off for a robust challenge on Rooney and Chelsea coach Carlo Ancelotti said the defender "could have been lucky."
However, the Italian was pleased with his side's commitment, saying: "The performance was really good. If you do not play well you cannot beat Man Utd".
The fixture that has so often been billed as a virtual title decider in recent seasons initially had something of a low-key feel about it, with Chelsea in the unusual position of being all but out of the title race with over two months of the season still remaining.
Ancelotti opted to go with Fernando Torres and Nicolas Anelka as his front-men, leaving Didier Drogba on the bench.
Ferguson also picked two from three - with Rooney and Javier Hernandez starting together and Dimitar Berbatov among the substitutes. It was the same strike force from Saturday's 4-0 win over Wigan Athletic.
The manager said before the game that Rooney was fortunate to be playing having escaped a ban for his off-the-ball elbowing of Wigan's James McCarthy but he was not the only pantomime villain on show as United gave a special welcome to Ashley Cole.
The England defender had been fined and investigated by the police for shooting a member of the Chelsea staff with an air gun at their training ground. One United fan held up a sign saying: "Don't shoot Ashley" while all of them roared "shoot" every time he touched the ball.
In an open, attacking game, United gradually took control and Rooney should