The Danes held a shock 2-1 aggregate lead going into the second leg and seemed on course of a famous upset when they scored the opening goal, yet in the end they crumbled as the Red Devils ran riot, led by rookie Marcus Rashford and Memphis.
Romer struggled to cope with the Netherlands winger and admitted after the match that it is an experience he will never forget.
“I’ve never been so close to crying after a match as I was today,” the right-back, who was sent off in the closing stages, said.
“Memphis is the best player I have ever faced. It was difficult to do anything about it when he plays like that.
“He is the best. He can do anything. He went inside, outside, turned me around and used his incredible pace to get past me.”
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However, the 22-year-old conceded that the match as a whole was a great reality check for him and his team-mates.
“We’d been looking forward to the match and had dreamed about playing in such a stadium all our lives,” he said. “But it brings you down to earth when you go there and get smacked around.
“What we had been looking forward to was quickly forgotten. We saw how big the step is to the Premier League.”