Kobbie Mainoo made his first start of the season for Manchester United but their Under-21s were dramatically edged out 4-3 by the Class of '92-owned Salford City in the EFL Trophy.
Mainoo, 18, set up two goals including Shola Shoretire's early opener.
Conor McAleny and Matty Lund turned the game around before Omari Forson and Shoretire made it 3-2 to United.
But Lund equalised from the spot on 87 minutes and completed his hat-trick with another penalty in stoppage time.
Salford's win ensured top two Bolton and Stockport will progress from Northern Group E.
Teenager Mainoo was on the bench for the Manchester derby on Sunday as he continues his recovery from an ankle injury that has kept him out for several months.
Elsewhere, Tyler Smith hit a first-half hat-trick as Bradford beat Manchester City's Under-21s 3-0 to ensure progress from Group F along with Barnsley.
West Ham won 1-0 at Newport County to take charge of Southern Group H thanks to Gideon Kodua's second-half strike.
Alejo Veliz's first Tottenham goal was in vain as Peterborough came back to win 3-1 to go top of Southern Group D.
Emmanuel Fernandez cancelled out the Argentine striker's early downward header before the break and Ricky-Jade Jones and Kwame Poku turned the game around for the hosts after the break.