Five minutes after the restart Demba Ba headed Shane Ferguson's cross on to the bar and Papiss Cisse stooped to head the rebound towards goal.
However, keeper David de Gea clawed it on to the post and survived claims that the ball had crossed the line.
Sir Alex Ferguson: "The goalkeeper has done fantastically, actually, to get to it, but if the rule is the whole ball has got to be over the line, then it's not a goal.
"But I would be disappointed because I thought enough of the ball is over."
We were saved by a blind linesman at Goodison Park when we took a point from Everton with a similar goal, but the luck changed against Man Utd.
But . looking on the good side . we took a point on Merseyside; had the goal been given on Sunday it wouldn't have made any difference.