Arsenal moved to within one point of the Premier League top four and extended their unbeaten run in all competitions to 17 games with victory at Bournemouth.
The Gunners took the lead thanks to a spectacular own goal from Cherries midfielder Jefferson Lerma, who volleyed Sead Kolasinac’s cross past Asmir Begovic from 15 yards.
Joshua King, making his comeback after four games out with an ankle injury, finished off a swift counter-attacking move to bring the hosts level seconds before half-time.
But Pierre-Emerick Aubameyang scored what proved to be the winner after the break when he converted Kolasinac’s cross for his eighth Premier League goal of the season.
After beginning the weekend in sixth, Bournemouth drop two places to sixth and have now lost their past three league matches.
The Cherries were aggrieved early on when David Brooks had a goal ruled out for offside, with replays suggesting he was marginally behind Shkodran Mustafi when the ball was played.
But that proved to be the catalyst for a confident display from Arsenal, who secured their fourth Premier League away win of the campaign – equalling their tally for the whole of last season.
After three successive home draws against Liverpool, Sporting Lisbon and Wolves, it was essential Arsenal got back to winning ways.
Emery left German playmaker Mesut Ozil on the bench and was without French striker Alexandre Lacazette due to a groin injury.
But Arsenal were still strong enough to consign Bournemouth to a third successive defeat as Emery’s decision to switch to a back three for the first time paid dividends.
Bournemouth thought they were ahead early on, but David Brooks was flagged offside as he slotted home King’s through ball.
Arsenal went up the other end and Lucas Torreira rattled the foot of the post with a fierce shot, with Alex Iwobi only able to lash the rebound high and wide.
Arsenal took the lead in the 30th minute when Lerma accidently volleyed Sead Kolasinac’s cross past Bournemouth goalkeeper Asmir Begovic as he stretched in a failed attempt to clear.
Iwobi drew a smart stop out of Begovic as the visitors looked to double their advantage before the break, but instead their run of not leading at half-time this season continued.
Cardiff are the only other top-flight side yet to hold a half-time lead in the league this season and King’s smart finish with the last meaningful kick of the opening 45 minutes ensured Bournemouth went in level.
When Aubameyang spurned a good chance after Henrikh Mkhitaryan had rolled in his team-mate, Arsenal fans began to call for the introduction of Ozil.
But the supporters who made the trip to the south coast were celebrating the lead in the 67th minute.
Aubameyang made amends for his earlier miss, sliding in to score from six yards after another Kolasinac cross.
Ryan Fraser shot straight into the arms of Bernd Leno as Bournemouth chased a second equaliser.
Lerma almost atoned for his own goal but struck a post with his low drive before Leno had to be alert to push the ball behind after it looped towards goal off the foot of Sokratis