The 1-0 result was United’s first win in the competition this season and came on a night when the club paid tribute to legendary former captain Sir Bobby Charlton.
Charlton passed away on Saturday aged 86. Old Trafford held a minute’s silence ahead of Tuesday’s game and manager Erik ten Hag was among those who helped lay a wreath in memory of one of the club’s greatest ever players.
As the match got underway, United endured a difficult first half as Diogo Gonçalves hit the post and Mohamed Elyounoussi’s follow up was deflected wide inside the first five minutes.
Lukas Lerager’s shot was well saved by Onana early in the second half before United started to attack the Copenhagen goal – first when Rasmus Højlund drove into the box, then when Christian Eriksen was denied by Kamil Grabara’s diving stop.
Substitute Alejandro Garnacho also had an excellent chance to put the home side ahead when he was through on goal from a counterattack, but a heavy touch meant the ball could be safely gathered by Grabara.
Minutes later, however, United took the lead through Maguire – a player whose form has often been maligned by fans – as he headed into the ground and into Grabara’s net from Eriksen’s excellent cross.
It would prove to be a crucial goal for United and Maguire, who was stripped of his captaincy over the summer and appeared to have fallen out of favor with ten Hag.
With the game opening up, Garnacho and Scott McTominay both missed chances to wrap up the victory, and those squandered opportunities almost cost United as Copenhagen was awarded a penalty for McTominay’s high boot towards Elyounoussi.
Jordan Larsson stepped up to take the spot kick and secure a draw in stoppage time but Onana produced a superb save to deny the visitors – batting away the penalty with a strong right arm.
The Cameroonian international has made several errors since joining United this season, including in a Champions League defeat against Bayern Munich last month. The penalty save went some way to atoning for those mishaps, and Onana was duly mobbed by his teammates immediately after his heroics.
“I’m very pleased, it was a narrow escape as we needed to win,” ten Hag told reporters after the match.
“We worked very hard to get that win. It was a poor first half but then, to come into the game, score that goal, and then concede a soft penalty. So it was important as we needed a win today.”
Asked about his penalty save, Onana said that he was “just doing my job, being calm, not under pressure and making myself big, waiting as long as possible and making the save.”
He also heaped praise on Maguire for scoring the winning goal, saying: “He was the hero tonight and I am very happy for him. It was a good performance again from him, but we have to continue like this and, for sure, we will be stronger.”
The crucial win puts United third in its Champions League group, one point behind Galatasaray and six behind Bayern, which defeated the Turkish side 3-1 in Tuesday’s other Group A game.
United’s next game is at home against rival Manchester City on Sunday: win that and you’d think the club’s challenging start to the season will be well on the road to recovery.