Sir Alex Ferguson had no complaints with the result after seeing Manchester United beaten by Chelsea, but felt aggrieved by big decisions.
The Red Devils, who have already wrapped up the Premier League title, slipped to a 1-0 defeat at Old Trafford on Sunday.
A deflected effort from Juan Mata three minutes from time settled the contest, before Rafael saw red late on for kicking out at David Luiz.
Ferguson admitted afterwards that his side were far from their best, but feels referee Howard Webb did them few favours.
He told Sky Sports: "The team took their foot off the pedal. There was no edge to the game all day. I think Chelsea deserved to win. "Unfortunately it was controversial, it always is when we play Chelsea, but we can't complain because we didn't play well enough.
"It was a bit of a lucky goal, it has deflected off Phil Jones. I can't make any excuses in terms of the performance. Certainly refereeing decisions went against us. They surrounded the referee all day, four or five players all the time."
On Rafael's dismissal, Ferguson added: "He was elbowed and he retaliated. That always happens, the player that retaliates always gets the bigger penalty. "It was quite clear that Luiz has elbowed him twice. It was rash what he has done, he's a young lad and he should know better. "I wouldn't say it was violent conduct. I don't think the referee has seen it at all, he's gone with the fact that Luiz has rolled about. I think that has convinced him it was a red card."