Chelsea suffered our first defeat of the Barclays Premier League season after being reduced to nine men in a frantic second half at Stamford Bridge.
Having fallen two goals behind early we clawed our way back into the game and level, only for Branislav Ivanovic and Fernando Torres to be sent off within minutes of each other, allowing United to prise back control of the game and grab a dubious winner through substitute Javier Hernandez.
United were two up inside 12 minutes after an unfortunate own goal from David Luiz and a Robin van Persie strike that exposed Chelsea’s early weakness down our left-hand side.
The Blues gradually came back into it though and when Juan Mata curled a free-kick into the far corner just before half-time, we looked as though we could yet force at least a point.
Seven minutes into the second half Ramires had headed us level and the momentum was with Chelsea, but it would be short-lived.
Just after the hour Ivanovic was dismissed when he brought down Ashley Young who was through on goal, and he was soon joined by Torres who was wrongly shown a second yellow, for simulation, after he had been yellow-carded at the end of the first period.
To make matters worse, United’s winner 16 minutes from time, courtesy of substitute Javier Hernandez, was offside, the Mexican poking home after coming back from beyond Chelsea’s defensive line.
Two changes were enforced on Roberto Di Matteo with John Terry suspended and Frank Lampard injured in midweek, so there were recalls for Gary Cahill and Eden Hazard, who both featured in last weekend’s win at Tottenham.
With both the captain and vice-captain missing, it was left to Petr Cech to lead the side out against a United side that had not won at Stamford Bridge since 2002.
The visitors paired Wayne Rooney with Van Persie in attack, flanked by Antonio Valencia and Ashley Young. Rio Ferdinand started in a familiar-looking backline.
The first action of the game came courtesy of Van Persie, who 35 yards from goal was able to turn David Luiz and shoot hard but straight into the arms of Cech. That was after two minutes, and 60 seconds later the Blues were behind, with the same figures involved.
Chelsea lost possession high up the pitch and United characteristically countered, eventually Rooney pulling back into the box for Van Persie, whose right-footed effort struck the post before bouncing back into play and into the net via the backside of David Luiz, with little the defender could do.
Conceding early to United is never a good thing, as it allows them to sit deeper and pick you off on the counter-attack once possession is lost.
This is exactly what happened after 11 minutes, as Rafael was given the ball on their right and afforded the time to release Antonio Valencia. Chelsea were nowhere near tight enough, and the Ecuadorian crossed low through the legs of David Luiz into the box, where with Cahill stretching but out of position, Van Persie was unmarked to fire his side two goals to the good.
Chelsea were of course having plenty of territory and possession, but too frequently there was no killer pass inside the final third, with Torres, Oscar and Ivanovic all guilty of misplacing or overhitting balls.
David Luiz lost possession inside his own half and allowed Rafael to cross, but fortunately no more damage was done with the United man unable to pick a team-mate. Our defender almost made amends at the other end, when his powerfully-struck free-kick was goalbound until the legs of David De Gea knocked it away. It was unorthodox but effective from the United keeper, and shorty afterwards Hazard drove just wide after beating Michael Carrick on the edge of the box.
Those efforts aside it was hard to see where Chelsea were going to make a breakthrough, despite seeing less of the ball United still carried more of a threat. That would change in the final 10 minutes of the half though, with Chelsea gaining more and more momentum until haf-time.
First, a low John Mikel Obi cross bounced off Jonny Evans and out for a corner off the outside of a United post. From that set-piece, Cahill rose highest and was unlucky not to pull a goal back, Rooney blocking the ball on the line though De Gea would likely have got there anyway.
A couple of minutes later the United goalkeeper produced what could be the save of the season so far to preserve his side’s two-goal advantage. Juan Mata crossed to the far post and found Torres, who did everything right with his header, but somehow the keeper was able to claw it back into play when a goal looked the only outcome.
Next time Chelsea came forward we would be rewarded for an extended spell of pressure, and it would be Mata, again, who came up with the goods.
Hazard had been tripped by Rooney 25 yards from goal, and the little number 10 was on hand to bend a terrific free-kick into the far corner, leaving De Gea with no chance.
This gave Chelsea the impetus to drive forward once more and when De Gea’s miscued clearance fell to Torres, he released Mata inside the United box but this time he could only poke straight at the goalkeeper and the score remained 2-1.
With 45 minutes still to play, however, there was surely now hope that something could be taken from the contest.
Mata had an early effort blocked following a corner but Chelsea were lucky not to concede a penalty when David Luiz blocked Valencia’s cross with his hand. There was no intent but the Brazilian’s arm was raised.
We regrouped quickly and just over a minute later we had levelled.
Oscar’s brilliant pass into the area found Mata, and when he couldn’t get a shot away he clipped the ball across goal to the far post, where Oscar met it and lifted it into the packed goalmouth, allowing Ramires to run onto it and send a header into the back of the net.
Now the momentum was right behind us. Hazard worked De Gea quickly after the goal, driving low towards the near post.
Having spent the last 20 minutes on the back foot, were United strong enough now to come out and attack once more? United had never lost a Premier League game after going 2-0 in front, a run lasting 246 matches.
Just as we were wrestling back control of the encounter, so we were losing it. Ashley Young was sent clear of the Chelsea defence as United broke, and although there was no intent, the in-pursuit Ivanovic sent the winger crashing to the floor a their legs tangled.
Referee Mark Clattenburg paused to assess the situation, which included a nearby David Luiz, but opted to produce the red card and reduce Chelsea to 10 men.
The dismissal prompted reshuffles on either side. Sir Alex Ferguson sensed victory and introduced striker Javier Hernandez, Di Matteo brought in Cesar Azpilicueta to shore up the defence.
Daniel Sturridge was about to replace Torres, when the Spanish striker was given a second yellow card, this for simulation after being clearly fouled by Evans. He had also been yellow-carded in the first half for a late yet innocuous challenge.
This game had it all, and the controversy was not going to stop there.
With Ryan Bertrand on for Mata and Azpilicueta for Oscar, Chelsea were playing with only Hazard as a recognised attacking threat, and United were pouring forward. The counter-attack would now be exclusively Chelsea’s.
After blowing a two-goal lead the visitors were unlikely to let a two-man advantage go to waste, and so it proved.
After Cech had saved a low Van Persie shot and clawed the loose ball away with his feet, it fell to Rafael inside the box to drive it back at goal. He miscued somewhat, though the ball fell to Hernandez to poke it home from two yards. Only Hernandez had been offside when the ball was struck, but the linesman did not notice and the goal was allowed to stand.
The last throw of the dice for Di Matteo was to bring on Sturridge, in place of the excellent but clearly tired Hazard.
For all the huff and puff that would follow, we could not gain possession for long enough to put the ball into dangerous areas, and so we are beaten at home for the first time since May, and our unbeaten run in the 2012/13 Premier League comes to an end.
But on a different day, with luck on our side, things could have been ever so different at Stamford Bridge.
Chelsea (4-2-3-1): Cech (c); Ivanovic, Cahill, David Luiz, Cole; Ramires, Mikel; Mata (Bertrand 71), Oscar (Azpilicueta 65), Hazard (Sturridge 81); Torres.
Unused subs Turnbull, Romeu, Marin, Moses.
Goals Mata 43, Ramires 52
Booked Torres 45, Mikel 75
Sent Off Ivanovic 62, Torres 65
Manchester United (4-4-1-1): De Gea; Rafael, Ferdinand, Evans, Evra (c); Valencia, Carrick, Cleverley (Hernandez 64), Young; Rooney (Giggs 73); Van Persie.
Unused subs Lindegaard, Anderson, Scholes, Nani, Welbeck.
Goals David Luiz (OG) 3, Van Persie 11, Hernandez 74
Booked Rooney 43, Valencia 90+1
Referee Mark Clattenburg