Eddie Nketiah came off the bench to seal a hard-fought victory over West Ham United in the first home game of the new season.
Expectations were high following an impressive showing last weekend against Fulham but the Gunners struggled to hit the same heights.
After a difficult start Alexandre Lacazette opened the scoring in Arsenal’s first chance of the game but were pegged back on the stroke of half time when Michail Antonio bundled home.
The Hammers forward had further chances to score and even smacked a header onto the crossbar before super sub Nketiah snatched victory for Mikel Arteta’s men.
Arsenal made three changes from the opening-day victory over Fulham although one was forced on them in the warm-up. Kieran Tierney was initially named in the starting XI but pulled out before kick-off and was replaced by Sead Kolašinac who joined Dani Ceballos and Bukayo Saka in the team.
Arteta has favoured a back three more recently and although the shape of the team changes in different scenarios there was a more defined back four than there has been for a while. Whether it was the system or just one of those days, the Gunners struggled to find any sort of rhythm with wayward passing and poor control.
While Arsenal were trying to find their feet, the Irons had chances to take the lead with Angelo Ogbonna heading directly at Bernd Leno and Declan Rice firing wide.
But the first time things clicked for the hosts they took the lead, following a VAR check. Saka sent Pierre-Emerick Aubameyang clear to the touchline and his lofted cross was perfect for Lacazette to head home.
Saka had a chance to double the lead minutes later after good play from Willian but the youngster lost his composure and ballooned his effort over the crossbar. It wasn’t all one-way traffic though as Gabriel Magalhães was fortunate not to be penalised for handball in the box with the new stricter rules now in place.
That didn’t deter West Ham and they drew level on the stroke of half time. Jarrod Bowen fed Ryan Fredericks on the overlap and his low cross was swept in by Antonio, who managed to get ahead of Rob Holding.
The Gunners dominated the opening exchanges after the break but it was Antonio who went closest to scoring but Gabriel did just enough to put him off and Leno gratefully grabbed the ball on the line.
The visitors enjoyed a strong sustained spell of pressure but Arsenal managed to keep them out before Nicolas Pépé replaced Willian.
But again, it was Antonio who was denied, this time by the crossbar when he rose highest to meet a cross.
The Gunners lacked any real creative threat, which only emphasised the need for a new midfielder, and Nketiah replaced Lacazette in the hope he could nick a winner and he did just that.
Saka played the ball to Ceballos that cut through the defence and the Spaniard squared the ball to Nketiah for a simple tap-in. There were half-chances for Aubameyang, Pépé and Nketiah to add gloss to the scoreline but David Luiz came on to help see out the game.