Rooney converted from the spot to register his fifth goal of the season
By Phil McNulty
Chief football writer at Old Trafford
Arsene Wenger was sent from the dug-out in fury after Abou Diaby's own goal gifted Manchester United victory at Old Trafford and wrecked Arsenal's flawless start to the new season.
Arsenal were on course for a fifth successive victory in domestic and European combat when Andrey Arshavin's magical finish gave them the advantage over the Premier League champions just before the interval.
Sir Alex Ferguson's side had struggled to make any impact against Arsenal's resilient rearguard - but the shape of the game altered dramatically in the space of five minutes around the hour mark.
Arsenal keeper Manuel Almunia needlessly fouled Wayne Rooney after 59 minutes to allow the England striker to equalise from the penalty spot.
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And the transformation in the game and the atmosphere inside Old Trafford was complete when Diaby, in a moment from his nightmares, headed Ryan Giggs' free-kick into his own goal in front of an ecstatic Stretford End.
Arsenal were shattered as their previous good work was squandered and boss Wenger's misery was complete when he was sent from his technical area by referee Mike Dean for kicking away a plastic bottle in frustration when Robin van Pertration when Robin van Persie's injury-time strike was ruled out for offside.
United keeper Ben Foster was culpable when he allowed Arshavin's 25-yard shot to fly in, but he was the hero when he prevented Arsenal taking what could have been an unassailable two-goal lead just after half-time as he blocked Van Persie from six yards when he seemed certain to score.
Van Persie also struck the bar before Diaby's calamitous own goal as a highly-anticipated encounter finally sparked into life after the break.
Ferguson surprisingly left Dimitar Berbatov and Michael Owen on the bench and opted for width in the shape of Nani and Antonio Valencia - a formation that failed to trouble Arsenal in a disjointed first 45 minutes for the champions.
Much rested on the shoulders of Rooney, and he almost fashioned an early breakthrough when he set up Darren Fletcher in the fourth minute, but the Scotland midfield man failed to find the target from 10 yards.
Arsenal were able to re-introduce Van Persie and Arshavin to their starting line-up after the midweek Champions League win against Celtic, and they posed the biggest threat to United in an opening period lacking in quality until the Russian's wonderful goal.
Van Persie created a chance for himself inside the area, but was blocked by Patrice Evra before Arshavin capped an eventful few seconds by giving Arsenal a lead they just about deserved five minutes before the interval.
Arsenal had clear penalty claims rejected by referee Dean when Fletcher appeared to handle when he challenged Arshavin in the area - but as play progressed the little striker stunned Old Trafford by regaining possession and unleashing a rising angled drive from 25 yards that flew beyond Foster.
It was a moment of joy for Arsenal and Arshavin, but miserable for England keeper Foster, who should have done much better after getting his hand on the ball.
Foster went some way towards making amends for his mistake two minutes after the restart, making a vital block with his leg as Van Persie stole in on more wonderful work from Arshavin inside the area.
Arsenal goalkeeper Almunia was the central figure when United equalised after 59 minutes, making an ill-judged dash from his line and felling Rooney as he went away from goal. Rooney recovered to send Almunia the wrong way from the spot and United's hopes were revived.
Referee Dean took the unusual - but correct - step of booking both Rooney and Wes Brown in the same incident as they hacked at Diaby. And Van Persie almost inflicted more punishment on United with a swerving free-kick that rebounded back off the bar with Foster beaten.
If Arsenal were knocked back by conceding a penalty, Wenger was beside himself in his technical area after 64 minutes when his side gifted United a second goal.
Giggs could only direct his free-kick on to the head of Diaby who, with no other player in close attendance, inexplicably directed a header past Almunia into his own net.
The setback understandably knocked the stuffing out of Arsenal and Wenger made a change after 78 minutes, sending on Eduardo for Denilson. The striker received a hostile reception from the Old Trafford crowd in the wake of the controversy over his alleged dive in the Champions League against Celtic.
But their hopes of restoring equality suffered a blow shortly after when Arshavin limped off after appearing to sustain a muscle injury as he chased Van Persie's through ball.
As Arsenal pushed for the equaliser, they predictably left spaces at the back and United almost cashed in. Substitute Berbatov slashed a shocking finish wide and Nani was denied by Almunia.
But Arsenal's mood was summed up by the sight of a disbelieving Wenger being dispatched from the technical area after he thought Van Persie had equalised, only to see his joy cut short by a linesman's flag.
And the sight of Arsenal's manager being escorted towards the tunnel only increased the joy around Old Trafford as Manchester United celebrated a crucial three points.
