United's Under 23s recorded a vital late win the Premier League Cup as Reece York struck five minutes from time to ensure the Blades have a fighting chance of making it through the group.
In a game not helped by the pouring rain pre-match or the constant blustery gales during it, Kean Bryan had put United in control after just 90 seconds.
A free-kick from the right was initially saved by Doncaster Rovers goalkeeper Declan Ogley but Bryan had the simple task of tapping home the rebound from close range.
The game that fell into a lull with possession football on the rain-sodden pitch and United struggled to build on their early momentum.
Benny Read cut inside from the left and fired an effort which was comfortable for Ogley before the visitors struck back, Joe Wright tapping home from close range in similar fashion to Bryan.
Jake Eastwood had to be alert either side of the break to make a couple of good saves and United stepped it up on the hour mark when Read once again cut in from the left and took aim, this time his effort cannoning back off the post.
Harry Sheppeard, Sam Ackroyd and Simeon Oure were all introduced as United pushed for a winner and they got it with just over five minutes to go.
Just after Eastwood had once again been called into action to make a vital double stop, the subsequent Rovers corner turned into a counter-attack for United, with Ackroyd slipping in York who calmly fired home at the near post.
It means United go to Everton at the end of the month with a fighting chance of getting out of Group B.
Blades: Eastwood, Ferguson (Sheppeard 46), Bryan, Broadbent, Belehouan, Neal (Ackroyd 74), Freeman, Lundstram, York, Greaves (Oure 61), Read.
Unused: Dewhurst, Cantrill.