Further evidence of Arsenal's lack of concentration came when Diaby produced a foul throw, but if that was comedy of sorts, there was nothing funny about the Frenchman's challenge on Steinsson which followed.
He slid in and clearly planted studs on Steinsson's standing leg at ankle height, and was given his marching orders by referee Chris Foy.
Down to 10 men, Arsenal needed to hit back quickly and almost snatched an equaliser when Toure's shot deflected off Gallas and skidded narrowly wide.
The Gunners were rocked when Matthieu Flamini hesitated on the edge of the box, the ball found its way to Taylor and his side-foot shot arrowed into the corner via Gallas's ankle.
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Interview: Arsenal manager Arsene Wenger
Game over, it seemed - and the end of Arsenal's fading title hopes, but then everything changed as on the hour mark Arsenal woke up, and Bolton went to sleep.
From Fabregas's corner, Gallas stole in completely unmarked at the far post to volley in and hand Arsenal a lifeline they had barely deserved.
They were level six minutes later, however, when Van Persie crashed in from the penalty spot after Gary Cahill brought down Hleb.
Van Persie had a chance to win it for Arsenal after substitute Theo Walcott cut the ball back to him but the Dutchman fired high and wide from 12 yards.
But he was not to rue his miss as Arsenal managed to scramble a victory when Fabregas's shot was deflected twice, the final touch off the unfortunate Samuel, and keeper Ali Al Habsi could not keep it out.
Bolton boss Gary Megson: "I don't feel unlucky. Angry isn't the right word because we are all angry with ourselves.
"That result today was a result which came from committing suicide.
"We just fell apart from 64 minutes. We gifted them the first goal, and the second goal was poor. And then we started to panic a little bit."
Arsenal manager Arsene Wenger: "I am very proud of our performance. The first half we didn't play badly but everything went against us.
"Their first shot on target was a goal, we had a player sent off and just before half-time they score a second.
"But we did absolutely everything to win the game and we got a very important victory for us.
"I was not upset with the sending-off of Diaby because his foot was a bit high.
"I feel it was more a protective tackle than an aggressive one but he was too high - I don't complain."
Bolton: Al Habsi, Steinsson, Cahill, Andrew O'Brien, Samuel, McCann, Campo, Taylor (Hunt 78), Guthrie, Davies, Diouf (Giannakopoulos 78), Hunt (Rasiak 81).
Subs Not Used: Walker, Cohen.
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