Manchester United surged nine points clear at the top of the English Premier League with an edgy 3-1 derby victory over Manchester City on Saturday.
City had not won a league game at Old Trafford since 1974 and their hopes of ending that depressing sequence were dashed as Wayne Rooney and Louis Saha struck before halftime.
Although Hatem Trabelsi pulled a goal back for City with 18 minutes remaining, Cristiano Ronaldo eased United's jitters when he tucked in a late third.
City's misery was complete when Bernardo Corradi stupidly got himself sent off in stoppage time when referee Graham Poll showed him a second yellow card for a blatant dive.
United, looking to stop Chelsea winning a hat-trick of championships, now hold their biggest lead in a title race since winning the title in 2001.
They are unbeaten in the league since September and head the table with 44 points from 17 games, scoring 38 goals in the process. Chelsea, who host Arsenal on Sunday, have 35 points from two games fewer.
"There are a lot of hurdles to navigate but I don't see any reason why we can't do it," manager Alex Ferguson told Sky Sports. "With us playing before Chelsea we can relax now and watch the game tomorrow and support the Gunners."
LATE STRIKE
United dominated in terms of chances, although City were always in with a shout until Ronaldo's late strike condemned Stuart Pearce to his first loss at Old Trafford since taking over as manager.
The former England hard man would not have enjoyed watching City's sloppy defending, which contributed to all three of United's goals.
Rooney's opener, his 50th goal in the Premier League, was a superb strike from the edge of the penalty area, but two City defenders failed to cut out Ronaldo's low cross.
Rooney was denied a second by a last-ditch tackle from Richard Dunne and then his ferocious drive forced goalkeeper Nicky Weaver into a smart save as United threatened to run riot.
City gradually got a foothold into the game, however, and should have equalised when Micah Richards headed narrowly wide after indecision in the United defence.
Greek striker Georgios Samaras stung Edwin van der Sar's fingers with a volley as City matched United with some admirable attacking football of their own.
Seconds before halftime, however, another poor piece of defending, this time when Trabelsi lost possession, allowed Gabriel Heinze to fire in a cross shot that Saha touched past Nicky Weaver in the City goal.
Weaver failed to return for the second half after being injured trying to deny Saha, and he was replaced by Sweden international Andreas Isaksson.
Trabelsi made up for his earlier error after 72 minutes when he surprised Van der Sar with a curled shot that cannoned in off the underside of the crossbar.
Any hope of a point disappeared when Dunne allowed a cross to slip under his foot and Ronaldo supplied the finish from close range in the 84th.
