The Dutch youngster played his second game of the season following a start at Northampton Town in the EFL Cup and he was on the pitch for 74 minutes, crossing in the lead-up to Zlatan Ibrahimovic's winner as the Reds kept the momentum going following last weekend's win over Leicester City.
"It's important to get the three points," Fosu-Mensah told MUTV after the final whistle. "We lost in Holland [to Feyenoord] and it was a must-win game for us.
"The last game at home against Leicester we did very well. Our attitude was very good and we wanted to maintain that and that's what we did tonight."