Captain Victor Musa scored a first-half double hat-trick, with Jim Thwaites also netting three, in an utterly dominant display from Adam Lawrence’s young Reds.
Leeds offered greater resistance after the break and scored through Kenneth Mensah, although only after James Bailey had thumped one home to reach double digits. Dan Armer and Gabriel - an U14 on as a substitute - brought up United's dozen late on, with the latter scoring twice.
Victory and three points keeps United in the U18 Premier League North title race. Lawrence's side trail Manchester City by five points, but have a game in hand on the Blues, who defeated Wolves on Saturday.