Referee Mark Clattenberg made made a hash of key decisions which ultimately cost Chelsea three points in an ill-tempered 2-3 defeat for Chelsea against Manchester United at Stamford Bridge.
He misjudged that Branislav Ivanovic fouled Ashley Young in a goal-scoring position and that Fernando Torres dived to receive a second yellow card.
The Blues were reduced to nine men after coming back to 2-2 from a 0-2 deficit after just 12 minutes.
An unlucky David Luiz own goal and a Robin van Persie strike had put United into the driving seat.
However Chelsea, responded from their slumber to snatch a wonder free kick goal from Juan Mata on the stroke of half time.
Within eight minutes of the restart, the Blues were level through Ramires.
But then referee Mark Clattenberg became the focus of attention with the two sendings off and United never looked back.
Once they took the lead again with 15 minutes remaining the game was all over.
United took the lead in most fortunate of circumstances on four minutes.
Taking advantage of a ball lost in midfield by Eden Hazard, the visitors broke quickly with quick interchanging by Wayne Rooney and Ashley Young, resulting in Rooney crossing low from the right into Chelsea's penalty area.
In-running Robin van Persie smacked a vicious right-footer against Petr Cech's crossbar. The ball bounced back and it hit David Luiz's waist and back again into the empty net.
It Got worse for the league leaders eight minutes later when another sizzling attack in the right saw Antonio Valencia, this time arrow the perfect driven ball into the path of Van Persie again. The former Arsenal striker made no mistake by belting the ball past a hapless Cech.
David Luiz almost got the Blues back in the game on 24 minutes when a blistering free-kick from 25 yards, dipped in front of David de Gea who misjudged the flight of the ball, correcting himself late to kick the ball away. Hazard then had a low shot on goal, which De Gea handled well in a more conventional way.
Chelsea hit the United post when Mikel's low drive ricocheted off Jonny Evans's shin and onto De Gea's right upright.
Cary Cahill had a powerful header on 35 minutes from the resultant corner by Juan Mata which De Gea did well to parry away as the Blues forced he pace before half - time.
De Gea produced a wonder save four minutes from he break when a clipped Mata cross was met powerfully by Torres, but his header was clawed out of the goal from De Gea.
With seconds ticking b, Wayne Rooney upended Mata on the edge of the United area.
After referee Mark Clattenberg issued a yellow card for Rooney, Mata then took the ball and curled the perfect left footer over the United wall and wide of the dive of De Gea to bring the home side back into the game.
The second half started as the first ended with Chelsea in the ascendancy.
United has a credible shout for a penalty ignored as Valencia's shot hit the right hand of Luiz inside his own area on 52 minutes.
And they got their just rewards a minute later when Ramires headed home from eight yards after Oscar clipped an inch-perfect byline cross to the Brazil midfielder.
Oscar had started the move with a defence-splitting ball to Mata who pulled the ball out of the air from over his head with a majestic trap - he followed the move up by sending the ball back across goal where it fell invitingly for Oscar to assist in Ramires' goal.
Just as it seemed everything was going Chelsea's way, Branislav Ivanovic was shown the red card for fouling Young who had got ahead of the Blues defender on 63 minutes.
It was an unlucky break for the right-back and United boss Sir Alex Ferguson responded by replacing Tom Cleverly with striker Javier Hernandez as he decided the game was now moving in their favour.
Chelsea boss Roberto Di Matteo decided that he needed to sacrifice a midfielder and Oscar was the one to shore up their deleted defence with Cesar Azpilicueta coming on.
Chelsea were reduced to nine men on 68 minutes when Clattenberg deemed a long run by Torres who then appeared to be clipped by Evan was a dive.
Having already been given a yellow card just before half-time for a foul, Clatternberg brandished a second yellow followed by the red.
Di Matteo was forced into a similar substitution brining on defence-minded Ryan Bertrand for Mata.
Ferguson replied by bringing on veteran Ryan Giggs for Rooney. Within seconds on, 75 minutes United, with a two man advantage had breached the
Chelsea rearguard to take the lead again.
A Van Persie drive was parried by Cech onto the goal line. He ball was cleared to
Rafael who arrowed it back into the six-yard box where Hernandez stroked it home.
However the Mexican appeared to have been in an offside position when Rafael shot came to him. C
helsea's final substitution, with eight minutes to go, saw Daniel Sturridge replace Hazard.
But United are experienced enough to run the clock down which is what they did.
Chelsea remain top of the pile, but heir confidence will no doubt be dented by this defeat.
Teams: Chelsea, Cech, Ivanovic, Cole, Luiz, Ramires, Torres,Mata, Oscar, Mikel, Hazard, Cahill Subs, Turnbull, Romeu, Moses, Marin, Sturridge,Azpilicueta, Bertrand
Manchester United: De Gea, Rafael, Evra, Ferdinand, Evans, Alencia, Rooney, Carrick, Young, Van Persie, Cleverley, Subs, Lindegaard, Anderson, Giggs, Hernandez, Nani, Welbeck, Scholes
Referee. Mark Clattenberg