Arsenal fell to a narrow defeat at Cologne on Thursday night but will still progress into the knockout stages of the Europa League as Group H winners.
An uninspiring evening at the impressive RheinEnergieStadion saw the Bundesliga's bottom club secure a 1-0 win through Sehrou Guirassy's second-half penalty to keep their own qualification hopes alive.
On the back of a morale-boosting victory over north London neighbours Tottenham at the weekend, Arsene Wenger's second string could not maintain the feel-good factor for long.
Defeat here ended a perfect run in this competition so far this season but, following a draw between Red Star Belgrade and BATE Borisov in the group's other game, the Gunners will finish top.
Much of this game followed the same pattern as the drab goalless draw at home to Red Star in their last Europa League outing, as Wenger again made 11 changes.
The impact of his youngsters, as well as the likes of Jack Wilshere and Olivier Giroud, has stagnated in recent games in this competition as they all aim to make the step up to Wenger's Premier League side.
Ainsley Maitland-Niles had a chance inside the opening two minutes, earning a corner as Timo Horn turned his shot behind after the youngster had been picked out by Wilshere.
The returning David Ospina was forced into a superb stop as he dived to turn Jhon Cordoba's drive behind, with the striker looking to open the scoring as he did at the Emirates Stadium in the return tie.
Francis Coquelin then drilled his own long-range strike just wide before hitting the post with another effort after breaking into the box on the half-hour mark.
There was very little action for the remainder of the half, with Wenger opting to introduce Alex Iwobi at the interval as Danny Welbeck, only just back from a groin injury, made way.
The second half was similar to the first in terms of a lack of quality and it was hardly surprising that the opening goal of the game came from the penalty spot.
Guirassy went down under pressure from Mathieu Debuchy and - after referee Vladislav Bezborodov awarded a penalty - the former Lille youngster dusted himself off to slot the resulting spot-kick home.
Arsenal skipper Per Mertesacker, returning to the stadium where he made his professional debut 13 years ago, almost headed the visitors level soon after but his effort was punched clear by Horn.
Wilshere tested the Cologne goalkeeper as falling behind seemed to stir Arsenal from their slumber, but they could still not muster a clear-cut opportunity to draw level.
Substitutes Reiss Nelson and Eddie Nketiah squandered late chances to salvage a positive result before Horn saved superbly from a stoppage-time Wilshere strike.
Arsenal now face a final group game at home to BATE in a fortnight's time, although the outcome will have a bigger baring on Cologne's European ambitions than their own.