United posted a 2-0 win at Aston Villa to clinch a place in the Barclays Under-21 Premier League elite phase.
Warren Joyce's side needed to win the final group game to qualify - either via the top two or the best third-placed side depending on how Villa fare in their final fixture - with Bebe and Federico Macheda conjuring up the goals in the second half.
It was no more than the Reds deserved for a fine performance after the break and Macheda's late second ensured there was no route back for the Midlanders.
Villa were the brighter side in a low-key start with Danny Johnson firing wide and Graham Burke returning Jonny Sutherland's loose kick-out with interest but the ball deflected behind the goal.
Mason Watkins-Clark was relieved to only receive a yellow card after a wild tackle on Davide Petrucci as things were rather scrappy in a tussle mainly played out in midfield. Villa's first-team boss Paul Lambert moved to the bench to offer advice to Gordon Cowans and Sutherland had to scamper to keep out a Burke shot from a difficult angle.
United struggled to test Calum Barrett as Petrucci mishit a shot wide after some delightful skill before Ryan Tunnicliffe's inspiring run could not find a finish from Macheda in the middle due to Bradley Lewis' last-ditch tackle.
A Macheda cross looped off Watkins-Clark and over his own bar and the same player was later grateful to Barrett for keeping out another deflection. Tom Thorpe and Michael Drennan traded off-target efforts but it was no real surprise that the first half ended goalless.
Alexander Büttner failed to reappear due to injury, with Sean McGinty taking his place, and the Reds started