Wayne Rooney scored his fourth goal in three games as Manchester United beat Fulham 1-0 at Craven Cottage to move 10 points clear at the head of the Premier League table on Saturday.
Rooney's 79th-minute strike, his 10th league goal of the season, came after the game had been held up for 10 minutes before half-time because of a floodlight failure and increased the pressure on second-place Manchester City ahead of their clash with Liverpool on Sunday.
For long periods it looked as though Alex Ferguson's side would have to be content with a point, with Fulham surviving first-half pressure before growing stronger after the break.
But after hitting the woodwork three times in the opening half, United finally made the breakthrough when Rooney capitalised on a mistake by Fulham's Philippe Senderos.
Fulham's hopes of springing a surprise were dented when Dimitar Berbatov was denied the opportunity to face his former club after picking up a hamstring strain in the mid-week win over West Ham United.
And the early signs were that this would be a testing afternoon for the home side, when they somehow survived a period of intense United pressure just 10 minutes into the game.
Mark Schwarzer, the Fulham goalkeeper, produced an outstanding save to deny Nani's deflected header and then looked on as Patrice Evra latched onto the loose ball and sent a close-range shot against the bar.
Rooney met the rebound with an overhead kick that was cleared off the goal-line by Sascha Riether and the danger was eventually snuffed out moments later when Schwarzer again reacted well to save from a second Evra shot.
To Fulham's credit, they were not rattled, responding immediately through John Arne Riise, who saw a dipping left-foot half-volley tipped away by David de Gea.
The United keeper has been under pressure in recent weeks following reports Ferguson is considering a summer move for Stoke City's Asmir Begovic, but the youngster's first-half display provided a timely reminder of his talents.
He was beaten, however, by Bryan Ruiz's left-foot shot from the edge of the box moments later and was relieved to see the effort deflect away to safety off the post.
It was an exhilarating start, with the defences of both sides looking vulnerable.
Fulham centre-back Brede Hangeland stood out among his team-mates, but the Norway international showed that even he was liable to a mistake when his misdirected header from the resulting corner hit Schwarzer's bar.
The woodwork again came to Fulham's aid 10 minutes before the interval when United conjured the best move of the first half.
Evra surged down the left before moving the ball on to Nani, who picked out Tom Cleverley, positioned on the edge of the Fulham area.
Cleverley's first-time lay-off teed up Rooney, allowing the England striker to curl a right-footed shot that came back off the post.
In the second period, the home side began to assert themselves more as the leaders found it harder to find a way through to Schwarzer's goal.
The keeper was forced to save from Robin van Persie's header four minutes after the restart as United threatened to carry on from where they had left off.
But from then on it was Fulham who looked the side more likely to make the breakthrough before Rooney eventually struck.
Ruiz had the best of the chances, first when he shot wide after De Gea had parried Riether's shot in the 72nd minute.
Then the Costa Rica forward saw a close-range header cleared off the line by Rafael.
It was Rooney, though, who produced the moment of composure that eventually decided the game when he advanced from halfway after a mistake by Senderos.
With Aaron Hughes backing off, the striker moved into the Fulham box before placing a right-foot shot inside the far post.