Boss Unai Emery admitted Aston Villa got lucky after fighting back to beat AZ Alkmaar.
Ollie Watkins’ winner put them on the brink of qualification in the Europa Conference League after a 2-1 home win.
Yet, the fightback started in controversial fashion when Diego Carlos levelled after Boubacar Kamara had blazed over and referee Luis Godinho mistakenly awarded Villa a corner.
Vangelis Pavlidis gave the hosts a deserved lead but last year’s semi-finalists are now facing an early exit.
Villa are second, behind Legia Warsaw on head-to-head, and a point from their final two games will seal progress from Group E.
Emery said: “It was a very good chance for Kamara, it was fantastic, but it was not a corner, it’s clear, and after this mistake we score.
“I’m very happy because when we are winning a game like tonight we can understand this competition better and the processes we’re trying to build.
“I’m very proud of our work in this competition. We’re getting better.
“We scored one that was offside more or less. We have to accept the referee’s decision, always.
“I’m very proud of our work in this competition. We’re getting better. AZ are a very good team. I’m very happy. The reaction when they scored the goal was fantastic.”
Villa started brightly and Clement Lenglet headed in Leon Bailey’s cross – after Pavlidis blocked Watkins’ goalbound header – only for the winger to have been ruled offside.
Yet the hosts lost their way as the half wore on, Pavlidis tried to lob Emi Martinez and Alkmaar finished on top with Pavlidis testing Martinez.
It turned out the striker was just getting his eye in as he opened the scoring six minutes into the second half.
Villa were caught out by Riechedly Bazoer’s ball over the top and Pavlidis outpaced Lenglet to beat Martinez.
The hosts were not behind for long, though, when Diego Carlos nodded in Bailey’s corner – after the officials had missed it was Kamara who blazed over from six yards.
Villa had the initiative and it was no surprise when Watkins popped up with the winner with nine minutes left, nodding in Douglas Luiz’s clever pass.
Alkmaar boss Pascal Jensen said: “The interesting thing I was looking at was can we compete better in the first game (a 4-1 loss)? In Alkmaar we lost because we conceded two easy goals.
“I was a bit shocked when we started off, we conceded an early goal and we were fortunate it was disallowed. We were very unfortunate to concede a corner which wasn’t, they scored from it and the whole stadium woke up.
“I contacted the fourth official and I asked him and he said ‘I don’t know.’ I think in international competition VAR can come on the radio and help but he didn’t. With all the technology and extra eyes it shouldn’t be possible.”
