Noni Madueke struck late to earn Arsenal a hard-fought 1-0 win over Nottingham Forest at the City Ground.
The Gunners struggled to create clear chances for much of the contest, with neither side really threatening in the first half.
Forest defended resolutely and frustrated Mikel Arteta’s side, who dominated possession without finding enough quality in the final third.
Arsenal increased the pressure after the break and turned to their bench in search of a breakthrough as the game entered its closing stages.
The decisive moment finally arrived in the 80th minute when Madueke’s effort took a deflection and beat Matz Sels to put the visitors ahead.
Forest, without the injured Morgan Gibbs-White, threatened to equalise when Murillo curled just wide of the top corner.
But the win keeps Arteta’s side three points behind league leaders Manchester City and continues their strong start to the season, while Forest were left to rue another game in which they struggled for attacking cutting edge.