Arsenal qualified for the knockout stages of the Europa League with a goalless draw at home to 10-man Sporting Lisbon in a game overshadowed by a potentially serious ankle injury to England forward Danny Welbeck.
A victory for Qarabag against Vorskla Poltava meant this 0-0 draw was enough to secure the Gunners' progress from Group E as Sporting had Jeremy Mathieu sent off late on for scything down Pierre-Emerick Aubameyang as he burst through on goal.
But it was Welbeck's injury just before the half hour mark that was the main talking point from a largely forgettable Emirates Stadium encounter.
The 27-year-old has overcome serious issues in the past, missing large chunks of his career with knee problems.
This latest setback comes on the day he was named in Gareth Southgate's latest England squad for the forthcoming games against the United States and Croatia.
He was carried off the pitch following an awkward landing after he had beaten Sporting defender Bruno Gaspar to a header and it was clear he was in need of help.
The incident knocked the wind out of Arsenal's sails but Welbeck's replacement Aubameyang hit the crossbar as the visitors offered very little in terms of an attacking threat.
But a 15th game unbeaten for Unai Emery's side at least assured them of European football after the turn of the year with two group matches left to seal top spot.
Arsenal enjoyed plenty of possession from the outset although the hosts were reduced to long-range efforts from Carl Jenkinson, again starting in the unfamiliar role of left-back, and youngster Emile Smith Rowe.
Mathieu almost gifted Arsenal the lead as he diverted Matteo Guendouzi's low cross towards his own goal before the ball was swept away.
The game was then stopped for several minutes after Welbeck contested a header with Gaspar before appearing to suffer an ankle injury on landing.
He required treatment on the pitch, including an oxygen mask and a leg brace, before he was taken off on a stretcher to be replaced by Aubameyang.
Arsenal's players, most notably Guendouzi, were clearly moved by seeing their team-mate in pain and the half did not really flow again.
After the break, Aubameyang hit the crossbar within the opening minute as he turned Henrikh Mkhitaryan's cross onto the frame of the goal.
The Gabon striker was certainly Arsenal's liveliest attacking outlet and he sent another shot just wide of Renan Ribeiro's goal as Arsenal looked to snatch the lead.
Alex Iwobi also failed to hit the target with a decent chance as Sporting's interim coach Tiago Fernandes turned to prolific forward Bas Dost from the bench in the hopes of leaving north London with three points.
Emery readied young striker Eddie Nketiah for his first appearance of the season but was forced to instead bring on Ainsley Maitland-Niles as Stephan Lichtsteiner pulled up injured and had to be replaced.
The game continued without any real chances of note, Mkhitaryan stabbing an Iwobi cross towards goal before Aubameyang saw an effort bravely blocked.
Aubameyang thought he had a late one-on-one to settle the contest but was fouled by Mathieu, who was shown a straight red card for the cynical trip.
That was the last of the meaningful action as Arsenal failed to score for just the second time under Emery - but it will be Welbeck's injury that dominates the fall-out.