Manchester United needed an extra-time penalty from Bruno Fernandes to scrape into the Europa League semi-finals after beating Copenhagen 1-0 on Monday.
In sweltering heat, United's young team controlled the lion's share of possession but had a hard time creating clear chances until Andreas Bjelland brought down Anthony Martial in the penalty area. Fernandes blasted the ball past the otherwise excellent goalkeeper Karl-Johan Johnsson to give United the 95th-minute lead.
First, VAR scratched off a United penalty for offside in the buildup. Just before the break Greenwood put the ball in the net after a lightning break down the right flank but the replay showed he'd been just offside when Marcus Rashford's pass was played.
That decision was a particular blow for United after the apparent breakthrough goal came just as the English team had seemed to be getting frustrated and taking increasingly speculative shots against a Danish team playing its first ever European quarter-final.
Copenhagen striker Mohamed Daramy muscled his way past the United defense to shoot in the 17th but had his shot blocked by Harry Maguire, and Jens Stage's follow-up was blocked, too.
United plays five-time Europa League winner Sevilla or English club Wolverhampton on Sunday in the semi-finals. They play their quarter-final on Tuesday.