Manchester United manager Alex Ferguson accused Chelsea's Brazilian defender David Luiz of acting like a "dying swan" in the incident that led to United defender Rafael da Silva being sent off in their encounter at Old Trafford.
United lost 1-0 to their London rivals, a result that means Chelsea can effectively secure a top-four finish and Champions League soccer if they beat Tottenham Hotspur at home tomorrow.
The veteran United manager conceded that his team did not deserve anything out of a game in which they failed to score at home for the first time in 67 matches in the league, but he was angered by Rafael's late dismissal.
The Brazilian tussled with his countryman Luiz before clearly hacking at his ankles, but the Chelsea defender did little to help his cause when he appeared to smile as he lay on the ground while referee Howard Webb brandished the red card.
"He [Rafael] retaliates, but he [David Luiz] quite clearly elbows him twice then rolls about like a dying swan and that convinces the referee," said Ferguson. "He was smiling. It's bad. What kind of professional is that?
"The ref has been bought by the fact Luiz is rolling about. But whether the ref will be doing anything about it, I doubt it very much.
"When a player retaliates, he gets punished the most. Luiz rolled about. You see that with these European, foreign and South American players.
"He [Rafael] was elbowed, he retaliated. That's what always happens - the player who retaliates always gets the bigger penalty and it was clear that Luiz elbowed him twice.
"It was rash what he did, he's a young lad and should know better, but retaliation never works.
"I wouldn't say it was violent conduct. The referee hasn't even seen it. I don't think he could see it at all, but he has gone with the fact that Luiz has rolled about on the floor and I think that has convinced him it was a red card."
United were incensed after Rafael's sending off, claiming that Chelsea's players had pressured Webb into his decision.
They had also claimed that Juan Mata's late winning goal, deflected in via Phil Jones moments earlier, had followed a foul on Wayne Rooney, although Ferguson, sportingly, said that was not the case.
"The referee's decisions went against us, I thought," said Ferguson. "They surrounded the referee all day; four and five players all the time, and I think that affected the referee.
But I don't think it was a foul [on Rooney]. We weren't getting anything from the referee anyway. It was a bit of a lucky goal - it deflected off Phil Jones, so we had bad luck with that.
"I can't make any excuse for my players in terms of their performance."
The controversy detracted from a superb result for the away side, but Chelsea interim manager Rafael Benitez refused to become embroiled in a war of words with his opposite number Ferguson.
"No, I was not very interested, because I have seen 200 incidents in the Premier League this year and it changes nothing," he said.
Instead, the Spaniard is focusing on securing an unexpectedly successful end to the season, which could see him leave the club having helped them qualify for the Champions League and win the Europa League.
"It's a massive win for us because we knew we needed to get six or seven points to guarantee the top four and, hopefully, we can stay there until the end," he said. "It was an important step forward."
He added: "This game was difficult, but [tomorrow against Spurs] will be even more important. It's crucial because winning means we will be there [in the Champions League], but it's even more important to them, so it should be a great atmosphere at Stamford Bridge.
"We will go and try to win because we know we can guarantee the top four."