The visitors enjoyed a good spell when Jabo Ibehre flicked a near post effort wide and Stephen Gleeson saw a couple of shots deflected off-target.
But Cresswell gave the hosts a 22nd-minute lead, firing low past David Martin after finding himself in space on the left-hand side of the penalty area.
The Blades finished the first half strongly with Phillips having a shot saved and Harry Maguire heading narrowly wide.
Gleeson struck the equaliser for the Dons in the 52nd minute with a fine shot from the edge of the area.
But Phillips put the Blades back in front in the 67th minute, scoring from close range after Billy Clarke had produced a surging run to the byline and played the ball across the face of goal, while the Dons were reduced to 10 men in the 83rd minute when Adam Smith picked up a second booking.