Jesse Lingard scored the only goal of the game as United's Under-21s earned a fully-merited 1-0 success against Southampton.
Warren Joyce's side were the dominant force throughout but only managed a solitary strike, netted at the start of the second half. Ben Amos remained untroubled for the full 90 minutes, until coming to clutch a cross in comanding fashion in stoppage time, as the Reds deserved to win by a greater margin.
The victory against the fourth-placed Saints takes United above Liverpool into second spot in the table with runaway leaders Tottenham the next opponents on Monday at Salford City Stadium.
Play was held up early on following a nasty clash of heads that led to both Marnick Vermijl and Calum Chambers being substituted. Vermijl needed four stitches, while Chambers required six, and the Belgian's replacement Reece James soon had an impact.
The left-back's excellent low cross was met by Lingard's stabbed shot and the ball hit the outside of the post to deny the Reds a well-worked opener. Nick Powell managed to run past keeper Cody Cropper but his pass was intercepted by skipper Jack Stephens and the teenager then hammered a deflected shot wide from Frederic Veseli's clever backheel.
Just past the half-hour mark, Ryan Tunnicliffe spurned a clear opening when blasting over the bar. The tenacious midfielder, who sent an early overhead kick wide, could not keep his effort down after Tom Thorpe headed an Adnan Januzaj corner towards goal.
Eight minutes later, a lovely turn of pace from Januzaj saw his cross fly across goal with Powell unable to convert with Cropper getting a crucial touch. Januzaj continued to give Matt Young a testing time in an orthodox right-wing role while the final attempt of the half came when Lingard forced a straightforward stop out of Cropper.