Alexis Sanchez converted a 92nd-minute penalty to give Arsenal a 1-0 win and a third successive stoppage-time victory over Burnley at Turf Moor.
The Gunners won both matches last season by virtue of last-gasp goals, a Sanchez spot-kick also proving decisive at Emirates Stadium in January, and the Chile international repeated the feat after James Tarkowski was adjudged to have pushed Aaron Ramsey.
Having won just one of its previous six Premier League away trips, Arsenal appeared set to drop more points on the road after an uninspiring performance in attack.
Arsene Wenger's side clearly missed the influence of Mesut Ozil, sidelined by illness, as it struggled to unlock a Burnley outfit which had previously conceded only twice in six home league matches this term.
But the last-gasp spot-kick proved all the visitors needed to leapfrog rival Tottenham Hotspur into fourth, with Sean Dyche's side missing its own opportunity to do exactly that.
Instead, Dyche's men were left to contend with yet another heartbreaking defeat to a team against which they have now lost 1-0 in each of the past three Turf Moor meetings.