Warren Joyce's side were under the quash for the majority of the first period, with Cameron Borthwick-Jackson having the only real opportunity. But it was Sam Johnstone and Axel Tuanzebe, who stood out for their defensive displays.
The Foxes' barrage continued in the second period, but an excellent chip from substitute Demetri Mitchell three minutes from time secured the win at the Leigh Sports Village.
Sam Johnstone - 8
One of the star players on the night, and the performance will go a long way to try and push Sergio Romero out of the no 2 jersey.
He made a number of significant saves, the best coming from Regan Poole's deflected howler, and showed his creativity with the assist for the goal.
Joe Riley - 5
Riley put in another decent performance in the back four, proving defensively sound throughout the contest.
However didn't offer much going forward, and gave away several unneeded fouls.
Regan Poole - 6
Poole was a key man in the heart of defence in a match where the defensive four were pushed to their limits.
He produced some good blocks to break up the play, with the near own goal been his only error on the night.
Axel Tuanzebe - 7
United will have the efforts of Tuanzebe to thank for keeping a clean sheet.
The 18-year-old produced another solid display, which is becoming a common phrase for the youngster, and could be knocking on Jose Mourinho's door soon enough.
Cameron Borthwick-Jackson - 5
Borthwick-Jackson made his return to the reserves, after his first-team antics last season.
It proved a solid return for the full-back after a injury lay-off, with a good chance in the first period, and an excellent cross that should have been converted.
Devonte Redmond - 4
Redmond looked good in possession at the Leigh Sports Village, but failed to set the pitch alight with his talents.
Redmond was moved into a deeper role with the absence of Sean Goss, and spread the ball well, but needs to be more imposing in both defence and attack.
Matty Willock - 4
One of United's best players at this level last season, there was expectation surrounding Willock, but he failed to impress in this opening match.
Like Redmond, he failed to impose himself on this match, and looked anonymous at times, however he did make vast improvements in the second period.
Matthew Olosunde - 3
United very much lacked any attacking prowess throughout the match, and that was partly down to the out of character performance of Olosunde.
The American only showed glimmers of what he can do, with some fancy footwork and one or two drives forward, but will need to improve quickly.
Josh Harrop - 6
Harrop was United's main creator on the day, and if he continues like that it could be a rewarding season for the youngster.
Harrop looked to pull the strings, but the lack of striker saw him struggle, some feisty challenges displayed his determination and has the potential to be a vital component to the side.
Tosin Kehinde - 4
Kehinde struggled on the night, playing out on the left, for a player who is more suited to a central role.
However, when he did have it, he looked confident on the ball, but produced little apart from a cut-back for James Weir, but is likely to improve in his debut season at U23 level.
James Weir - 4
The lack of creativity and service behind Weir, saw his performance suffer, especially in the first period.
His unfamiliarity to the role was clear, as he proved careless on the ball, but vastly improved as he was pushed out on the left after the introduction of Mitchell.
Substitute - Demetri Mitchell - 7
Mitchell's performance was the definition of that of a super-sub.
Mitchell's determination was clear from the off, he made a number of runs behind the defence and was rewarded as he finished the winning goal with a first-time lob.
Manchester United U23's will take on Southampton at the St Mary's Stadium on Monday, August 22 with kick-off at 7pm BST.