Arsenal secured a 3-1 Champions League Group H success against Partizan Belgrade in Serbia following an assured display.
Fine link up play between Andrey Arshavin and Jack Wilshere saw the former open the scoring before Brazil-born striker Cleo drew the hosts level from the spot after Denilson handled.
The game was turned on its head as Marko Jovanovic was dismissed for hauling down Marouane Chamakh inside the area and, although Arshavin failed to score from 12 yards, Chamakh headed home soon after and Sebastien Squillaci glanced in his first Gunners goal to seal the victory.
Impressive goalkeeper Lukas Fabianski, in for the injured Manuel Almunia, saved a late spot-kick from Cleo to thwart a grandstand finish.
Partizan enjoyed the lion's share of the ball during the opening exchanges and Cleo had an excellent opportunity to open the scoring as he stormed clear on goal.
He beat the offside trap, but he allowed Denilson to come back and make a fine last-ditch tackle.
Against the run of play, Arshavin spotted a gap in the opposition's defence and, with Wilshere finding his way into the penalty area, the Russian found the youngster with an incisive pass.
The chance appeared to have been snuffed out, but the England Under-21 international wriggled free before teeing Arshavin up with a deft back-heel and he hammered the loose ball past the hapless Vladimir Stojkovic.
Arshavin started running the show and he was thwarted as he went in on goal and he went close again as his goalbound chip was sensationally cleared by the diving Jovanovic.
Arsenal's inability to convert their chances came back to haunt them as the home side levelled from the penalty spot.
A harmless cross from the left struck Denilson and referee Wolfgang Stark had no doubts that he stopped the ball with his arm.
Local hero Cleo stepped up and calmly rolled past Fabianski, to the delight of the partisan crowd.
Arsenal huffed and puffed, but failed to regain the lead, despite dominating at the interval.
The hosts' chances appeared to evaporate ten minutes after the restart when Jovanovic was shown a straight red card for hauling down Chamakh.
But Arshavin failed to convert from 12 yards as his powerful effort hit Stojkovic's legs and rebounded to safety.
With Arsenal in control and making their man advantage count, they finally broke through.
Tomas Rosicky's excellent centre was headed onto the bar by Chamakh, but the former Bordeaux man was quickest to react and he nodded safely into the back of the unguarded net.
Defender Squillaci put the game beyond doubt as he met substitute Samir Nasri's corner to head home, but just moments after, a clumsy Kieran Gibbs challenge resulted in another penalty.
However, Cleo failed to set up a grandstand finish as Fabianski kept out his weak effort and the Londoners held firm with some comfort to make an impressive start to their Group H Champions League adventure.