The recent addition from Arsenal came off the bench in the second half during United's thrilling 4-3 victory over Sunderland.
Chido Obi-Martin made his Manchester United U18 debut on Saturday.AdvertisementAdvertisementBendito Mantato struck twice, with defender Reece Munro and midfielder Jim Thwaites also scoring for United on the day.
Obi-Martin took the pitch on 63 minutes and was immediately fielded at centre-forward.
Fellow new signing Samuel Lusale, who has joined from Crystal Palace, started for United on the day and was given the first-half on the flank before being changed.
Interestingly, fit-again Shea Lacey replaced Lusale for the second-half.