Louie Marsh netted a late winner, as United deservedly maintained their 100% record in pre-season.
For the trip to S60, Hamer and Ahmedhodžić returned to the starting XI having missed out in the midweek success at Harrogate. New signing Burrows made the bench, although Grbić missed out through illness.
A bright start that had seen Hamer have a couple of shots saved, United took the lead on ten minutes as SOUZA rose highest from Arblaster's corner to head home into the bottom corner. Moore dragged an effort wide following a swift counter attack, before Shackleton limped off and was replaced by Seriki.
United continued to dominate long periods and from an inviting Brooks delivery Moore headed against the post, before Arblaster received a yellow card for a lunge on Nombe. From a corner, moments after, Raggett saw his headed cleared off the line by the young Blades midfielder. Before half time, the excellent O'Hare was denied by Phillips, having continued to combine dangerously with Hamer.
Rotherham equalised three minutes into the second half, with HUNGBO applying the finishing touch at the back post, after the Blades failed to deal with a cross from the right. On 66 minutes, McCallum did well to keep the ball alive, but under pressure, Brooks couldn't seriously trouble Phillips.
The Blades deservedly won the contest late on when MARSH reacted first to slot on the rebound after Phillips failed to gather Peck's initial effort, as United four wins from four in pre-season.
Blades: A. Davies, McCallum, Arblaster (Dozzell 45), Hamer (Slimane 45), Moore (Marsh 79), O'Hare, Ahmedhodzic (Peck 68), Shackleton (Seriki 20), Robinson, Souza (Sachdev 79), Brooks.
Unused: Faxon, Curtis, Hampson, Burrows, Boyes.
Attendance: 6,291(2,867 Blades fans)