WEST Ham United were condemned to a third consecutive defeat as Arsenal came from behind to claim a 3-1 win over the Hammers.
Marko Arnautovic gave the Hammers the lead, only for Nacho Monreal to equalise before half-time at the Emirates Stadium.
And an own goal from West Ham debutant Issa Diop was followed up by a late clincher from Danny Welbeck.
Both sides went into the clash having lost both of their first two Premier League fixtures of the campaign.
And while Jack Wilshere made his Emirates Stadium return, Mesut Ozil was missing from the Arsenal squad - officially through illness but with some reports suggesting he was dropped after a fall-out with Gunners chief Unai Emery.
Either way, the Spaniard finally got his maiden win to kickstart his tenure despite questions remaining over the defensive ability of his side.
Another former Arsenal player made an immediate impact as goalkeeper Lukasz Fabianski kept out Henrikh Mkhitaryan's strike with a tremendous stop.
Aaron Ramsey nodded in the rebound but was flagged offside, before West Ham broke and Arnautovic arrowed an effort into the side-netting.
The Hammers grew into the contest and attacked a nervy Arsenal defence at any given opportunity.
That threat eventually led to the opening goal, with Arnautovic rifling home from the edge of the box after an exchange of passes with Felipe Anderson.
Emery's men responded well to their latest setback, levelling five minutes later as Monreal was on hand at the back-post to turn home Hector Bellerin's deflected cross.
Petr Cech denied the Hammers a second goal with Robert Snodgrass finding space in the box to test the Arsenal skipper on the stroke of half-time.
Arsenal introduced Alexandre Lacazette in place of Alex Iwobi at the break but it was Shkodran Mustafi who almost put the hosts in front soon after the restart - Fabianski again making a smart stop to keep out the German's header.
Lacazette's first opportunity came to him on the edge of the West Ham penalty area but he shot straight into the arms of the West Ham goalkeeper.
In an end-to-end start to the second-half, Pellegrini's men passed up another great chance to re-establish their lead.
Matteo Guendouzi was robbed of possession by Anderson, who broke forward and crossed for Arnautovic but he could not make a telling contact and Cech saved easily.
Arnautovic was then forced off injured and soon after his side were unfortunate to fall behind.
Pinball on the edge of the Hammers box saw the ball fall to Lacazette, whose cross cannoned off Diop and into his own net to put Arsenal ahead.
Fabianski kept out Pierre-Emerick Aubameyang's low drive and a superb long-range Ramsey effort while West Ham's late rally failed to produce an equaliser as Welbeck scored a simple goal to seal the three points for Arsenal.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article