Egypt international Elmohamady, who was declared fit for the match after shaking off a minor knock, played the whole 90 minutes of the match.
As usual, the 23-year-old was deployed as a right winger and once again produced an assured display.
Six minutes past the hour mark, an Elmohamady cross found Cristian Riveros in the area but the latter failed to divert the ball into the net.
But Elmohamady could have cost Sunderland dearly when he felled Samir Nasri in the area to give the Gunners a penalty in the second half.
Tomas Rosicky wasted the spot kick when his effort went high over.
Arsenal took the lead on 13 minutes when Cesc Fabregas blocked an Anton Ferdinand long pass from point-blank range near the center, to staggeringly divert it into Sunderland's net.
Bent brought the score level deep into injury time following a goalmouth scramble that resulted from an Elmohamady header.
Arsenal's Alex Song was sent off five minutes from the hour mark for two bookable offences, which took a toll on the London side's performance for the rest of the game.