Pierre-Emerick Aubameyang hit his eighth Premier League goal of the season to earn Arsenal a hard-fought win at Bournemouth.
The Gunners had drawn their last three league games but Aubameyang’s second-half strike was enough to extend their unbeaten run to 17 matches in all competitions.
Jefferson Lerma scored a remarkable volleyed own goal to give the visitors the lead at the Vitality Stadium, with Joshua King levelling for Bournemouth before Aubameyang scored to seal a 2-1 victory.
Unai Emery sprung a tactical surprise by starting with a three-man defence, the first time the Arsenal head coach has opted for such a system in the league since his appointment.
It paid off as Sead Kolasinac, playing as a wing-back, laid on both Arsenal goals as they moved to within a point of Chelsea in fourth place.
Alexandre Lacazette missed out with a tight groin, while the change in system meant Mesut Ozil was only among the Arsenal substitutes.
The hosts 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 an arrowed shot, with Alex Iwobi only able to lash the rebound high and wide.
Bournemouth were certainly the better side as the visitors struggled to adapt to a new formation, with Callum Wilson heading at Leno as the Cherries continued to push for the opener.
King’s pace was causing problems for the recalled Sokratis Papastathopoulos, who was shown a yellow card for hauling the Bournemouth man to the ground on the edge of the penalty box.
But it would be Arsenal who took the lead with half an hour on the clock, Lerma turning a Kolasinac cross past Begovic with a finish any top Premier League striker would have been proud of.
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.
Arsenal were again pushing for a second but, having lost possession in the Bournemouth box, a rapid counter-attack ended with King – back in the side following an ankle injury – converting past Leno.
Neither side could create anything of note at the start of the second-half, Aubameyang spurning a good chance after Mkhitaryan had rolled in his team-mate.
The Arsenal fans began to call for the introduction of Ozil but were soon celebrating the lead as Aubameyang slid in to score from six yards after another Kolasinac cross.
Ryan Fraser shot straight into the arms of Leno as Bournemouth chased a second equaliser, with Eddie Howe turning to Junior Stanislas and Lewis Cook off the bench.
Lerma almost atoned for his own goal but struck the same post as Torreira with a low drive before Leno had to be alert to push the ball behind after it looped towards goal off the foot of Sokratis.