Paul McGuinness' youngsters couldn't capitalise on their first-half dominance, as Sheffield Wednesday came from behind to earn a 2-2 draw.
The young Reds controlled the opening period of a match dictated by inclement weather, as high winds heavily affected play.
With the win in United's favour, the U18s started well as Oliver Norwood and Cameron Stewart both hit the woodwork. And United were soon 2-0 up after 22 minutes - right-back Scott Moffatt and attacker Nicky Ajose giving the Reds the lead.
Just before the break, however, Wednesday took advantage of the blustery conditions themselves, pouncing on United defensive confusion from a set-piece. With the wind in their sails - and behind them - they pressed on in the second half for an equaliser, while Reds goalkeeper Conor Devlin fended off several other opportunities.
United substitute Ravel Morrison could have won it late on when Ajose's clever through-ball sent him clear of the home defence, but the Manchester-born midfielder's finish went just inches wide.
It's a second consecutive draw against a Sheffield team, after last week's 0-0 stalemate with Wednesday's city rivals United. The U18s' next match - Saturday 4 April at 12:00 BST - is the rearranged fixture against Middlesbrough at Carrington.
United: Devlin; Moffatt (Brown 46), Wootton, Gill, Dudgeon; Curran, Tunnicliffe,
Norwood, Galbraith (Morrison 57); Stewart, Ajose.