Wayne Rooney scored twice as leaders Manchester United came from behind to beat Sheffield United.
Rooney made it six goals in his last seven matches
The Blades took a surprise lead when Keith Gillespie headed in Derek Geary's cross against his former club.
But Rooney hauled the visitors level when he coolly found the net from a Gary Neville cross.
Rooney won it on 75 minutes when he drilled in Patrice Evra's cross before Cristiano Ronaldo hit the crossbar and then blazed over from just three yards.
In the end, Sir Alex Ferguson's side should have won by a far bigger margin after they wasted a string of late chances, but the victory was enough to maintain their three-point advantage over champions Chelsea.
Rooney's form is a major bonus for United, who should have taken an early lead when Neville should have done better than drive straight at Paddy Kenny's legs when clean through on goal.
Sheffield United went ahead with virtually their first attack on 13 minutes after Rio Ferdinand failed to clear his lines wide on the right and Geary crossed for Gillespie to direct a perfect header back across Edwin van der Sar from eight yards.
The leaders almost hit back instantly when Neville's cross was headed at goal by Rooney and was brilliantly scooped away for a corner by Kenny.
Referee Mark Clattenburg rejected strong appeals from Manchester United for a penalty - when Louis Saha appeared to be unfairly shoved in the back by Rob Kozluk - and booked Ryan Giggs for protesting.
Manchester United pressed hard and the equaliser on the half-hour came when Neville crossed from the right for Rooney, who needed two touches before clinically dispatching the ball past a helpless Kenny.
Paddy Kenny was cleared to play despite an eyebrow problem
There was a second appeal for a penalty when Paul Scholes claimed he was held back by Alan Quinn just before half time, but again the referee disagreed.
The Blades were in no mood to allow United to take the upper hand after the interval as they were spurred on by the biggest crowd of the season so far at Bramall Lane.
Neil Warnock's side closed United down and their relentless work rate meant the title hopefuls were unable to enjoy as much possession as normal until the final 20 minutes.
The Blades suddenly found themselves back-peddling as United attack down both flanks with the much-improved Patrice Evra particularly effective down the left.
And it was from his pin-point cross that Rooney cracked home a rasping low shot to give Manchester United the lead.
Ronaldo should have settled it but he failed to properly connect just five yards from goal as a gilt-edged chance went begging.
The Portuguese then headed against the bar from a Giggs cross and the follow-up from Scholes was cleared off the line by Phil Jagielka.
Manchester United were rampant in the closing stages but Ronaldo's afternoon was capped off by the most embarrassing miss of the season when he scooped over a Giggs cross from three yards with the goal at his mercy.
In the end, it did not matter as Sheffield United never looked like clawing their way back for a point.
Their visitors now look forward to two mouth-watering fixtures against Celtic in the Champions League followed by the visit of Chelsea.
Sheffield United boss Neil Warnock:
"Our season starts now," he said. "When I saw the fixtures at the start of the season, I thought the games after this one would be crucial to us.
"I thought we might have been a few more points adrift, but we are not. We are in the mix and we can start scrapping for points from now on."
Warnock hailed his players, adding: "I couldn't have got any more from them."
Manchester United manager Sir Alex Ferguson:
"They were two marvellous finishes from Rooney. The first came from a run across the defender. He has caught him on the hop, off-guard, and it was a great strike.
"The second was terrific. Taking that kind of finish, when you are under pressure and you need to win, it makes it more special.
"They proved it was going to be difficult, but the important thing is we kept our patience, kept probing, and made some good chances."
Sheff Utd: Kenny, Kozluk, Davis, Jagielka, Geary, Gillespie, Law , Leigertwood, Alan Quinn (Kabba 86), Kazim-Richards (Nade 79), Hulse.
Subs Not Used: Morgan, Sommeil, Montgomery.
Goals: Gillespie 13.
Man Utd: Van der Sar, Neville, Ferdinand, Vidic, Evra (Heinze 80), Ronaldo, Carrick, Scholes, Giggs, Rooney, Saha.
Subs Not Used: Kuszczak, O'Shea, Fletcher, Silvestre.
Goals: Rooney 30, 75.
Ref: M Clattenburg (Co Durham).