United's U18s made it three without defeat as they came from behind to earn a point away at Crewe.
A stunning solo goal from half time substitute Angelo Capello earnt the Blades a share of the spoils.
United came close to going ahead on 18 minutes as Boyes cut inside from the left and struck the post with an effort on his right foot.
This would see a spell of Blades pressure and Potts was denied by the Crewe stopper shortly afterwards.
As the break approached the deadlock was broken but it was the Railwaymen who took the lead as a shot from just inside the area beat Kelly down to his right.
After the interval Crewe almost extended their advantage but an edge of the box strike bounced off the bar and away to safety.
United's pressure paid off this with 80 minutes on the clock as CAPELLO picked up the ball on the right beat three defenders on his way into the box and smashed home into the bottom left corner for a spectacular equaliser.
Blades: S. Kelly, Williams, Boyes, Neal, Weaver, Gordon, Beckley (Capello 45), Broadbent, Potts, J. Kelly, Ompreon (Viggers 68).
Unused: Chapman, Stainrod.