The Arsenal midfielder inexplicably headed into his own
net as United came from behind to stay in touch with leaders
Chelsea.
Arsenal had stunned the champions thanks to Andrey
Arshavin's rocket opener five minutes before the break.
But Wayne Rooney levelled from the spot before Diaby's
gaffe handed United the points.
Robin van Persie found the net in injury time but his
effort was chalked off after William Gallas had strayed
offside.
Arsene Wenger could not believe the decision on the
touchline and was promptly sent off for his protests.
Ryan Giggs then sparked United's comeback as he
threaded a superb pass through to Rooney on 59
minutes.
The England striker took one touch past Almunia and
contact was inevitable, with Rooney hitting the deck.
Almunia was booked and then had to pick the ball out of
the net as the United hitman sent him the wrong way with his
spotkick.
Van Persie hit the bar with a curling free-kick from
wide on the right three minutes later.
But the United fans were celebrating again within 60
seconds as Diaby headed Giggs' free-kick towards his own goal,
leaving Almunia stranded as the ball bounced in.
Dimitar Berbatov had a superb chance to round off the
scoring in injury time but he skewed his effort well wide.
Almunia made a save from Nani soon after before the
Portuguese winger blazed the rebound over.
IT'S NOT FAIR ... Arsene Wenger protests against
another decision against his team
