The difference between a good side and a title-winning side is the ability to play badly and come away with the points. United didn't deserve to take anything from that game, but the fact that they kept Liverpool out for the ninety minutes, and managed to snatch a goal themselves, shows us why they're 12 points clear at the top while we're struggling to keep pace.
Alternative interpretation: Lucky bastards.
EDIT: Don't worry, Paul. You'll feel much better once we stumble to a 1-0 defeat against Reading.