Paul McGuinness fielded an Under-17 line-up with a view to next season and the Black Cats made the better start to an entertaining fixture at the Academy of Light, Sunderland's training ground.
Jordan Blinco latched onto a Daniel Pybus pass early on but United's Dean Henderson saved well and the goalkeeper also denied the same player when he attempted a close-range header.
The Reds went close when Joe Riley powered down the right to cross and full-back Tyrell Warren failed to get enough power in his shot to beat Greg Purvis in the home goal.
Henderson was again worked by Steven McCarthy, and by the dangerous Blinco, but he had no chance with the opening goal. Andrew Nelson turned United skipper Axel Tuanzebe and, when Charlie Scott slipped, Ethan Robson was left in the clear to apply a precise finish for Sunderland.
In added time at the end of the first period, United retaliated with a speculative long-ranger from Rashford that bent and dipped into the corner to leave Purvis stranded. In a period of spectacular strikes for United at all levels, this will surely be another Goal of the Month contender.
Despite losing the speedy Demetri Mitchell, who was feeling unwell, McGuinness' side enjoyed more possession after the break. Croskery swept one chance over the bar following a fine pass by Rashford to pick out Cameron Borthwick-Jackson on the left but Purvis was largely untested.