Clint Dempsey struck two minutes into injury time for Tottenham Hotspur to rain on Robin van Persie's parade at White Hart Lane.
Van Persie had put Manchester United on course for a vital win when he scored his sixth goal against Spurs, but after a sustained period of pressure, Dempsey delivered Andre Villas-Boas's men a thrilling equaliser with less than a minute of the match remaining.
The American, who had missed a gilt-edged chance earlier in the second half, got on the end of Aaron Lennon's pull-back and slotted home after David De Gea had gone walkabout.
The draw means United are now just five points ahead of Manchester City after Roberto Mancini's men after their win over Fulham on Saturday.
"It was a big relief. I thought we dominated the complete game," Villas-Boas, the Tottenham manager, said in a post-match television interview.
"We could not get in behind them a lot but had 15 opportunities. We have talented players and we gave them different problems, the team came out very strong in the second half.
"I think the boys have embraced the spirit that we want to be in the Champions League next year, and you need to amass as many points as possible.
"We wanted to win, but it was an important point in the end due to the form United are in. A point can give us a lot of confidence."
Dempsey said: "It looked like it was going to be one of those days but I am happy we got a point."
Sir Alex Ferguson, the Manchester United, told the BBC: "We did so well at everything and we kept heading it out, the disappointment is not finishing them off. We had a lot of opportunities on the counter attack but our final ball let us down.
"It was a clear penalty-kick on Wayne Rooney but in no way was the linesman going to give that. He gave them everything else. We have not had a good record with this linesman, against Chelsea a few years ago he gave onside to Didier Drogba who was three yards offside, you remember those things."
About Tottenham's goal, he said: "They pumped the ball forward, maybe David De Gea could have got a better punch on it, but I will have to see it again.
"Tottenham were very committed and aggressive. I think they have a decent squad and a good team."