It may not have been Manchester United at their vintage best but a heroic late show from Andre Onana ensured their Champions League campaign is finally underway.
United looked to be eeking out a narrow 1-0 win at Old Trafford thanks to Harry Maguire's goal.
But when Scott McTominay conceded a penalty in the fifth minute of stoppage time, a familiar sense of dread crept in, with United having lost their opening two group games and they were now staring more dropped points in the face.
Onana, who has been widely panned for his displays in this competition this season, backed himself and pulled off a stunning penalty save with the last act of the match.
Mail Sport's Nathan Salt runs the rule over the teams at Old Trafford...
MANCHESTER UNITED (4-2-3-1)
Andre Onana - 8
Has had plenty of critics in this competition this season following mistakes against Bayern Munich and Galatasaray but this was his night. His decisive penalty save on this night of nights will be remembered for a long time to come.
Diogo Dalot - 6
Has impressed numerous times this season but this was far from his best. Copenhagen got the better of him in the first half but he rallied.
Raphael Varane - 6.5
The four-time winner offers United a wealth of experience and his partnership with Maguire, bar a couple of early ricks, never left Onana too exposed.
Harry Maguire - 7
What a night. All the talk of his mini redemption arc had been downplayed in some quarters for doing it against small teams. But his goal is huge for United's season and has rescued this Champions League campaign.
Sergio Reguilon - 6
Did well to get an hour in the legs on his return to the starting XI. Had flashes going forward but found himself penned back more often than not.
Sofyan Amrabat - 5
Tasked with filling the void left by Casemiro, this was another tough night for Sofyan Amrabat, who was second best in the midfield battle before being hooked at half-time.
Scott McTominay - 5.5
Found himself overrun in a first half where Copenhagen had the better of proceedings. Had bigger contributions in recent weeks and gave away the penalty in the final seconds.
Antony - 5
Still waiting to have a breakout game since returning to the side. Got little joy out of Sheffield United at the weekend and aside from a few bursts of pace he didn't cause Copenhagen enough problems.
Bruno Fernandes - 6.5
Often chastised for his mannerisms on the pitch but he can be quietly effective (when he isn't questioning decisions). His passing is among United's best and there is a reason Ten Hag rarely looks to bring him off.
Marcus Rashford - 6
Was unfortunate not to be squared the ball when United broke in numbers. Had one burst through on goal where a heavy touch let him down.
Rasmus Hojlund - 6.5
Showed good intensity leading the line and for a young guy learning on the job United fans are seeing plenty to be encouraged about. Not at his best, as he was against Galatasaray, but he kept the centre backs busy enough.
SUBS
Christian Eriksen (for Sofyan Amrabat, 46) - 7
Victor Lindelof (for Sergio Reguilon, 63) - 6
Alejandro Garnacho (for Antony, 63) - 6
Anthony Martial (for Rasmus Hojlund, 86)
FC COPENHAGEN (4-3-3)
Kamil Grabara - 6.5
Peter Ankersen - 5.5
Denis Vavro - 6
Kevin Diks - 6.5
Elias Jelert - 6
Lukas Lerager - 6.5
Rasmus Falk - 6
Diogo Gonçalves - 7
Mohamed Elyounoussi - 6
Viktor Claesson - 5.5
Elias Achouri - 7
