The Reds came racing out of the traps, storming into a two-goal lead inside the opening 13 minutes. Ethan Williams opened the scoring before Ethan Wheatley doubled United&aposs advantage just two minutes later.
However, United saw their lead halved when Emil Hojlund, the younger brother of Reds striker Rasmus, netted a 23rd-minute penalty. Copenhagen completed their comeback when Amin Chiakha found the net in the final minute of regulation time, meaning the points were shared.
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Though it was a disappointing conclusion for United&aposs youngsters, who have won just one of their opening four matches in Group A, it was another positive afternoon for Mainoo, who took another giant stride towards securing a first-team return. He was named on the bench against Fulham at Craven Cottage on Saturday but was not called upon by Erik ten Hag.
Mainoo, who is widely considered the jewel in United&aposs academy crown, has not played for the first team since July because of an ankle injury. He has, however, twice made the bench in recent weeks.
United want to build up his minutes at youth level before unleashing him back into the first-team fold. The Stockport-born player stored 45 minutes under his belt when the Reds&apos Under-19s faced Copenhagen in the reverse fixture at Leigh Sports Village last month.
Though he didn&apost score or provide an assist in Wednesday&aposs encounter, Mainoo did produce a polished display, bossing proceedings in midfield with his strength and technical ability. He was, at times, too skilful for the Copenhagen midfielders and defenders to deal with, highlighting his potential.
He went close to providing an assist early in the second half, sending Isak Hansen-Aaroen through one-on-one, only for him to make contact with the ball with a heavy touch and the chance broke down. He also proved useful in a defensive sense, cutting out a low cross into the United penalty area before strolling out from the back with the ball with ease.