Manchester United manager Erik ten Hag said his side are due a turnaround in fortune after collapsing to a 4-3 defeat at FC Copenhagen that left the Red Devils close to exiting the Champions League.
United led 2-0 inside half an hour in the Danish capital after Rasmus Hojlund struck twice against his former club.
But a red card for Marcus Rashford after a VAR review on 42 minutes changed the course of the game.
Copenhagen made the most of 13 added minutes at the end of the first half to level through Mohamed Elyounoussi and a Diogo Goncalves penalty.
Bruno Fernandes restored United's lead from the penalty spot, but the Danish champions struck twice in the final 10 minutes through Lukas Lerager and 17-year-old Roony Bardghji to secure their first Champions League win since 2016.
A third defeat in four games leaves United bottom of Group A.
But Ten Hag was unhappy at the award of both Copenhagen's first two goals and Rashford's dismissal.
The former Ajax boss believed Elyounoussi's strike should have been ruled out for offside and that the decision to penalise Harry Maguire for handball inside the area was harsh.
"We played very good until the red card. The red card changed everything. Then we concede two goals that should never count," said Ten Hag.
"Not only tonight. In this moment, we are in a season where we have to deal with many decisions against us.
"That's how it is. I'm sure it will turn. A season is long and at one point it will turn in our favour."
A ninth defeat in 17 games this season ramps up the pressure on Ten Hag's position.
However, the Dutchman believes there are positives to take from his side's performance before Rashford's harsh dismissal.
There appeared to be no intent from the England international when his studs caught Elias Jelert on the ankle as he tried to protect the ball.
United had produced arguably their best first 30 minutes of the season so far as two predatory finishes from Hojlund took his tally to five Champions League goals in four games.
"I have seen a lot of positives from this game but at the end we lose possibly some focus," added Ten Hag.
"Also, with 10 (men) we were still controlling the game.
"(The players are) very disappointed of course. We fought so hard, played so good and still we don't have one point."
United can still reach the last 16 as they sit one point behind Galatasaray and Copenhagen in the battle to join Bayern Munich in the knockout stages.
Ten Hag's men travel to Galatasaray in three weeks before hosting Bayern at Old Trafford on December 12.