Danny Welbeck scored late to help Arsenal secure a 1-0 win over Sporting Lisbon and mantain their perfect record in this season's Europa League group stages.
After a quiet first half, Pierre-Emerick Aubameyang forced two good saves out of Ruben Ribeiro while one-on-one, before Welbeck saw a header ruled out for a soft push.
Welbeck got his goal late on 78th, however, striking through Ribeiro after former Liverpool taking advantage of a defensive mistake.
Danny Welbeck scores to earn an important win for Arsenal against Sporting
The result means Arsenal are in pole position in Group E after three straight wins, and are close to securing a knockout spot with three games remaining.
In a first half lacking in clear-cut opportunities, Henrikh Mkhitaryan forced a decent save out of Ribeiro from an angled free-kick, while former Manchester United winger Nani struck narrowly over from long range.
Arsenal came out with more intent in the second half; Aubameyang forced Ribeiro into a good save from the right angle of the box, before the Brazilian goalkeeper got a fine left hand to the Gabon striker's shot from 10 yards while one-on-one.
The England star had his hardwork rewarded with a goal with 12 minutes remaining, striking low from 15 yards through Ribeiro after Coates had slipped as the last line of defence.
Arsenal have made it 11 straight wins out of 11 games this season
Arsenal saw out the last period with professionalism, earning their first-ever win in Portugal, and handing Sporting only their second home defeat in two years.
The Gunners recorded their 11th successive win in all competitions; their best run of wins since October 2007 (12 in a row).
This was Arsenal's first-ever away win in Portugal after previously failing to come away victorious in six European visits there (D3 L3).