Following a poignant remembrance of Sir Bobby Charlton and so many tributes to the club legend, it was time for the current crop to show the sort of spirit he embodied in such a vital match.
Copenhagen were the quicker starters, though, with Diogo Gonçalves’ first-time attempt hitting the post before Mohamed Elyounoussi’s effort was deflected wide by Harry Maguire.
Rasmus Højlund still got a sight of goal against his former club, firing over after latching onto a superb pass from Marcus Rashford.
Man United soon began to impose themselves more and a timely intervention from Peter Ankersen was required to prevent Scott McTominay from getting a clean shot off following some wonderful link-up play.
Even so, a lot of the hosts’ play was carried out at a pedestrian pace as they struggled to break down Jacob Neestrup’s well-organised side.
McTominay headed wide from Sergio Reguilón’s cross with their only notable opportunity in the rest of the first half as frustrations grew among the home fans at Old Trafford.
Erik ten Hag turned to Christian Eriksen before the restart, but the Lions had the first attempts of the second half, just as they had done in the first. Lukas Lerager met Viktor Claesson’s cutback with a strike that forced a brilliant save from Onana.
Eriksen then forced Kamil Grabara into action with a powerful strike that looked destined to find the bottom corner before being met by a strong hand.
The hosts finally got the moment they craved in the 72nd minute, as Maguire held off Rasmus Falk to meet Eriksen’s cross and head home his first goal of the season.
McTominay missed a golden opportunity to add a buffer, and then had the disastrous moment where he conceded a penalty for his challenge on Elyounoussi in the final seconds.
However, he was saved as Onana outfoxed Jordan Larsson to preserve the victory that ended Man United’s run of five consecutive UCL matches without a win.
That takes them one point behind second-placed Galatasaray, while also recording three successive wins across all competitions for the first time this term.
Copenhagen, meanwhile, are enduring a winless run of nine UCL matches that stretches back to 2016 and are bottom of Group A.
Flashscore Man of the Match: Harry Maguire (Manchester United)
