Alexandre Lacazette scored 29 seconds after coming on as a substitute to earn Arsenal a 1-0 win at Brighton & Hove Albion.
The decisive moment came in the 66th minute, with Bukayo Saka turning on the halfway line before setting up Lacazette, who took a touch before curling in a low shot into the bottom-right corner.
The best chances of the match came after half-time, with Brighton’s Bernardo twice going close before Pierre-Emerick Aubameyang’s close-range effort for Arsenal was saved by goalkeeper Robert Sanchez.
Gabriel Martinelli whipped a shot just over the crossbar before going off to be replaced by Lacazette, whose impact was instant.
Back-to-back victories move Arsenal up to 13th with 20 points.
Brighton have dropped to 17th, on 13 points, after extending their winless run to seven matches.