COPENHAGEN: Manchester United gave up a two-goal lead in a breathless 4-3 Champions League loss to FC Copenhagen on Wednesday that turned after Marcus Rashford was shown a controversial red card following a brace by young United striker Rasmus Hojlund.

The loss was a calamitous setback in United's hopes for last-16 qualification with Erik ten Hag's side fourth in Group A on three points with two group games still to play. Copenhagen are one point better off in second place.

"The red card changes everything," a beleaguered Ten Hag told TNT Sports. "Then it becomes a different game. I have seen a lot of positives from that game but in the end we have lost some focus.

"I think the (Rashford red) was a very harsh decision," he added.

United have two tough games to finish the group stage, at third-placed Galatasaray, who have four points, on Nov. 29 and at home against Bayern Munich, who have won all four group matches to book their spot in the last 16, on Dec. 12.

Hojlund fired United to a brilliant start in a roller-coaster first half, scoring his first when the game was just 171 seconds old by tucking in Scott McTominay's pass from close range.

The 20-year-old netted again against his former club in the 28th minute after a Kamil Grabara save sent the ball spinning practically to his feet.

The tide turned when Rashford was sent off in the 42nd minute for planting his foot on the ankle of Elias Jelert to protect the ball. The moment breathed new life into the home side and Mohamed Elyounoussi pulled one back three minutes later.

"We controlled the game until the red card. That changed the game," Hojlund told TNT Sports. "I think we switched off a little bit. We didn't think we would play with one man down.

"It gave them belief, I know how the crowd can help the team out. It gave them a big boost."

There was more misery to come as Copenhagen were awarded a penalty right before halftime after Harry Maguire's handball, and Diogo Goncalves slotted it past Andre Onana.

United briefly regained the lead when VAR awarded them a penalty for a handball which Bruno Fernandes calmly converted.

But they imploded in the final few minutes giving up two goals, in the 83rd when Lukas Lerager sprinted in to meet Rasmus Falk's cross and four minutes later when 17-year-old substitute Roony Bardghji fired home.

As the teams walked onto the pitch at Parken Stadium, Copenhagen fans unveiled a tifo that read "Your Theatre of Nightmares," a play on Old Trafford's nickname as the Theatre of Dreams and an apt description on Wednesday.

United became the first side to score two goals, have a player sent off, and concede a penalty in the first half of a Champions League match since Bayern Munich against Man City in November 2014.

The night marked the first Champions League loss for United in which they led by two or more goals. It was their first defeat after taking a two-goal lead in all competitions since a 5-3 loss to Leicester City in September 2014.

The defeat spoiled a feel-good return to Copenhagen for Hojlund, who was born in the Danish capital and whose younger brothers Emil and Oscar both play for Copenhagen.