Arsenal missed out on a chance to clinch direct progress to the Europa League last 16 after they went down 2-0 to PSV Eindhoven at the Philips Stadion on Thursday to leave top place in Group A to be decided in the final round of fixtures next week.
The Premier League leaders, who have already secured a place in the top two, needed just a point to be confirmed as group winners and avoid a playoff against a team dropping out of the Champions League. But PSV looked the far sharper team going forward and claimed a deserved win through second-half goals from Joey Veerman and half-time substitute Luuk de Jong.
Arsenal will now take a two-point lead over PSV into the final group fixture at home to bottom-placed team Zurich. PSV, who have now also guaranteed progress from the group stage, will visit Bodo/Glimt.
Mikel Arteta made six changes to the team that drew 1-1, with Gabriel Jesus and Bukayo Saka among those starting from the bench. A tight groin for United States goalkeeper Matt Turner, though, meant that regular No. 1 Aaron Ramsdale made his first Europa League appearance of the season.
While Arsenal dominated possession in the opening half, it was the hosts who were the more threatening of the two sides.
Twice PSV had the ball in the net in the opening 45 minutes only to be denied the lead by an offside call. First, on 19 minutes, Cody Gakpo looked to have furthered his burgeoning reputation with a fine dinked finish but the assistant referee's offside flag immediately went up.
It was a similar outcome two minutes before half-time. On this occasion, a VAR check for offside in the build-up halted PSV's celebrations after Xavi Simons had worked his way past three Arsenal players on the edge of the box through a combination of skill and lax defending.
But after Ruud van Nistelrooy's side began the second half by peppering Ramsdale's goal, there was a sense of inevitability when they took the lead in the 56th minute.
Substitute De Jong, now offering PSV a more direct threat in attack, played a big role, holding up the ball and then laying it off to the surging Veerman who crashed a left-footed shot past Ramsdale and into the Arsenal net.
Seven minutes later PSV's lead was doubled. De Jong was again at the forefront, rising ahead of the stranded Ramsdale to head Gakpo's corner into an unguarded net from six yards out.
The score could have been even more one-sided, with Gakpo having another goal ruled out for offside and De Jong going close again with a headed chance.
Arteta turned to Jesus and Saka to try and rescue something from the game off the bench, but there was nothing they could do to prevent Arsenal from suffering just their second loss in all competitions this season.