Dean Marney got through more than an hour as he stepped up his comeback with a second outing in the under-23s.
And striker Nahki Wells completed another 90 minutes as he heads towards full match fitness.
But that’s where the goods news ended on a difficult night at Curzon Ashton’s Tameside Stadium.
Michael Duff’s side had been unbeaten in their last four games but were torn apart by a rampant Blades’ side which went top of the northern group table.
United scored three times in each half and weren’t flattered by the scoreline as outstanding striker Tyler Smith bagged a hat-trick.
Burnley simply had no answer to the pace and finishing of the teenager but in the bigger picture there was at least encouragement in the game-time for Marney and Wells, who both looked sharper for the comeback fixtures they had played following injury in this competition at Nottingham Forest 10 days earlier and against United in a friendly a week ago.
The fast-starting Blades made their intentions clear from the start and were in front after just three minutes.
Smith had already given one warning shot across the bows when he got in behind the Clarets’ defence to slot the ball past Adam Legzdins and make it 1-0.
Dwight McNeil scored his second goal of the season for the U23s
And the Clarets couldn’t deal with the pace of the striker, who was constantly picked out on the break by the visitors to deliver a constant goal threat.
Duff’s side enjoyed some decent spells of possession after falling behind, United goalkeeper Jake Eastwood not helping his side’s cause with a couple of poor clearances that almost let Burnley in.
Harry Limb and Arlen Birch also shot wide from distance as Marney probed away and Wells made a couple of darting runs into the penalty area.
But two goals in quick succession just before the break spelled the end of Burnley’s comeback hopes.
Smith was the creator for the second goal as he again raced clear before pulling the ball back for former Hartlepool United midfielder Nathan Thomas to deliver a perfect first-time finish from the edge of the penalty area.
And in stoppage time it became 3-0 when Smith got away down the inside left channel and squared for Oliver Greaves to tap in.
The Clarets started the second period positively as Duff looked for a response but 10 minutes in, the Blades extended their lead with their first attack of the half.
This time the threat came down the right and when the cross came in, Smith continued his excellent night by powering the ball in from close range.
And the Sheffield-born youngster then wrapped up his hat-trick seven minutes later when he followed up to force the ball home after Legzdins had saved from Greaves.
Duff made a triple change with 63 minutes gone and three minutes later the Clarets pulled a goal back.
McNeil - along with the two senior players - had been one of the Clarets’ brighter performers and got his reward with a spectacular long-range strike to make it back-to-back goals on this ground.
Substitute Tinashe Chakwana, who had earlier shot wide with virtually his first touch, was then denied by Eastwood, who saved at the forward’s feet.
But the respite was only temporary as the Clarets were opened up again for Greaves to drive home his second goal on the break and complete a chastening night, McNeil denied the consolation of a second goal when his late free-kick was well saved by Eastwood.
Burnley: Legzdins, Birch, Flowers, Younger, Koiki, Bayode (Metz 63), Marney (Nabi 63), Howarth, McNeil, Limb (Chakwana 63), Wells. Substitutes: Stone, Clarke.
Sheffield United: Eastwood, Graham, Heneghan, Ferguson, Bennett (Cantril 79), Slater, Gilmore (Doherty 79), Thomas, Norrington-Davies, Smith (Parkhouse 74), Greaves. Substitutes: Hawkes, Warhurst.
Referee: Paul Brown