The Blades slipped to a narrow defeat on the penultimate pre-season outing against Championship opposition on Wednesday evening.
Former Blade Nick Blackman netted the only goal of an even contest for Derby, from a disputed penalty.
Boss Wilder named a strong side to face Nigel Pearson's Rams, with Wilson, O'Connell, Hussey and Fleck all experiencing Bramall Lane for the first time as a Blade, whilst Clarke was named amongst the substitutes having signed on Tuesday.
Chances in the opening minutes were at a premium, but midway through the first-half, two timely blocks denied Butterfield and then Christie within the same attack.
But as the half hour passed, Derby were literally handed the chance to seize the advantage, as referee Deadman adjudged Hussey had handled in the box from Christie's cross from the right. That allowed former Blade BLACKMAN the chance to calmly slot home into the top corner in front of the Kop.
Before half-time, Derby should have doubled their advantage, but Long managed to get enough on Ince's attempted lob to push the ball to safety before Hussey cleared the danger.
Inside the opening quarter hour of the second period, the Kop appealed in vain for a penalty for handball and McNulty fired over on the turn. On the hour, Clarke was introduced to the action.
With 17 minutes remaining and following a flurry of substitutes, Fleck sent a rasping drive over the bar from distance.
Neither side created much in the second-half, although Clarke looked lively on his United bow. Long denied a Elsnik from distance as the clocked ticked down and that proved to be the last action of the contest.
Blades: Long, Brayford, Hussey (K. Wallace 66), Fleck (Coutts 79), O'Connell, Basham (Reed 79), McNulty (Clarke 60), Sharp (Scougall 73), Done (Adams 68), Wilson, Duffy.
Unused: Ramsdale, Wright, Freeman, Whiteman.