Manchester United booked a place in the Europa League semi-finals thanks to a 1-0 extra-time win over Danish side Copenhagen on Monday night.
Bruno Fernandes scored the all-important goal from the spot, four minutes into the first half of extra time after Anthony Martial went down inside the box.
The Portuguese was one of the six changes coach Ole Gunnar Solskjaer made to his starting team from the side that beat LASK Linz 2-1 last week, throwing in arguably his best team.
Paul Pogba, Mason Greenwood, Marcus Rashford, and Anthony Martial were also recalled into the starting team at the Stadion Koln Stadium.
The Danes matched the Reds for long periods, even though United could have been home and dry in regulation time as they hit the woodwork eight times.
Mason Greenwood too had a goal disallowed for offside, much to the disappointment of the players.
In the end, it's that single moment that mattered most as Fernandes stepped up to powerfully find the right corner and give the Reds the lead.
The Reds joined Inter Milan in the last four, after they beat Bayer Leverkusen 2-1 earlier on.
Romelu Lukaku scored the winning goal after Nicolò Barella had given the Italians the lead. Chelsea-linked Kai Havertz scored the consolation for the Germans.