Chris Morgan paid tribute to United's next generation of talent, following Tuesday night's impressive 1-0 win over promotion chasing Rotherham United.
Ben Davies settled the contest from the spot in the 90th minute at Bramall Lane, after visiting skipper Craig Morgan had been adjudged to have impeded Harry Maguire in the penalty area.
Connor Dimaio made his full debut, whilst Louis Reed became the Blades youngest ever league player at the age of 16 years and 257 days. Otis Khan also featured as a second-half substitute and Morgan heaped praise on the players who ended the Millers' 16-game unbeaten run in League One.
He commented: "The youngsters were excellent. We made eight changes with Sunday in mind and the lads deserved their opportunity.
"They have worked hard for the U18s and U21s and earned this opportunity, as we thought they let nobody down.
"We want to give them a chance at this Club and we are delighted with how they played, not just technically, but more pleasing was they way we dug in and fought it out in the second-half.
"It was a tough game, as you would expect in a South Yorkshire derby, but the youngsters stood up to the challenge of Rotherham and dealt with everything they threw at us from start to finish.
"In seems funny that we are talking about Harry Maguire as the senior figure within the team, he is still only 21 himself, but again he was absolutely tremendous.
"It was a fantastic performance and an even better result."
On the major talking point of the contest, Morgan added: "We think it was a penalty. Craig Morgan had been warned twice by Mike Dean and from the technical area he appears to grab Harry (Maguire) again as the ball comes in, that is why Mike has pointed to the spot."