If evidence was ever needed that football was an unpredictable game, today at Bramall Lane was it.
On the 150th anniversary of the first ever football match at the Lane, League One leaders United lost to bottom club Hartlepool.
Skipper Michael Doyle and Harry Maguire netted for the Blades but two headers from Steve Howard paved the way for Hartlepool's win.
With Collins and Miller injured and McMahon suspended after accumulating five bookings, Westlake, Williams and Cofie all started for the Blades, whilst a number of Academy graduates were named on the bench.
After S2 fell silent to pay respects to the 3rd Battalion The Yorkshire Regiment, guests of the club at the match, the highly anticipated encounter kicked off with, expectedly, Westlake and Williams filling the full-back berths and Cofie partnering Kitson in attack.
The Blades began on the offensive and from the first corner, on two minutes, Doyle had a shot blocked but the visitors hit back and grabbed an early lead. The home side had a couple of opportunities to clear before Humphreys crossed from the left and HOWARD rose between two defenders to head past Long from close range.
It could have been worse for United as within five minutes both Franks and Howard, after Walton's neat pass, both failed to find the target despite having clear sights of goal.
The Blades settle and responded with chances. Kitson just failed to connect with Flynn's shot across goal and Flinders did well to palm away Blackman's shot after United's leading scorer cut in from the right. The Hartlepool goalkeeper, though, was not as competant minutes later when he spilled a long-range effort from DOYLE into his net for the leveller.
Before the break, Maguire fired over with his left-foot after showing composure on the edge of the box and Flynn almost got on the end of a Doyle chip into the penalty area.
In the first five minutes of the second half, Flynn had the ball in the net but he was adjudged offside from Cofie's misplaced shot and Hartlepool's Collins and Sweeney squared up to each other in the aftermath.
The stand-off seemed to galvanise the visitors, who regained the lead on 54 minutes. Horwood pulled back from the left and HUMPHREYS managed to squeeze the ball home at the near post.
McDonald fired across goal and Blackman shot wide after cutting in from the right as United tried to hit back once more, whilst Cofie's volley was straight at Flinders. Homegrown Chapell was the first of Wilson's replacements, taking over from Cofie, with Blackman switching to a central role.
After a Blackman free-kick was deflected wide and the corner weathered, things got worse for the Blades. From a long kick by Flinders, Poole delivered a cross from the left and HOWARD held off Maguire to direct a header past Long.
In the last 10 minutes boss Wilson made a double change, Ironside and Cresswell replacing Kitson and Doyle, but late on United could muster little, although there was a penalty appeal when Maguire was brought down - no decision was forthcoming and to add insult the defender was booked in the following melee.
The Blades defender did net late on. From Chapell's cross, Ironside headed down and Hill slid in with Flinders before MAGUIRE smashed home but there was no further time to mount a challenge for an equaliser.
Blades: Long, Westlake, Maguire, Hill, Flynn, Doyle (Cresswell 82), Blackman, McDonald, Kitson (Ironside 82), Cofie (Chapell 67), Williams. Subs: McAllister, Philliskirk, Kennedy, Coyne.
Hartlepool: Flinders, Humphreys, Collins, Horwood, Franks (Monkhouse 80), Walton (Austin 69), Sweeney, Richards, Hartley, Wyke (Poole 60), Howard. Subs: Baldwin, Holden, McHugh, James.