The Blades were good value for Wednesday afternoon's victory over Ipswich Town in the Professional Development League.
Terry Kennedy came through his first full 90 minutes of the season as United's high-energy display proved too much for the Suffolk side.
The Blades began well and McDonagh shot over before Chris Morgan's side grabbed the lead on 12 minutes. Coustrain was involved in the build up before PALING arrived at the back post to score.
Whiteman and McDonagh also had chances to extend the lead before half-time, whilst Coustrain went close just after the break.
As the Blades continued to dominate, Hamilton almost made a second for Paling before the home side doubled the lead just after the hour. From a corner, Banton challenged in the air and he or a defender may have got the final touch to beat the Ipswich goalkeeper.
The final 30 minutes saw the Blades in control without looking to extend the lead and the final whistle confirmed United have now lost just once in the last six U21s encounters.
Blades: Turner, Hendrie, Paling, Berry, Kennedy, Banton, Coustrain, Dimaio, McDonagh, Whiteman, Hamilton.
Unused: Scarisbrick, Willis, Wright, Calvert-Lewin, Heh.