The Blades led against the run of play when Billy Sharp nodded home his latest goal in front of the Kop, after Wes Foderingham had saved Brennan Johnson’s poor penalty in the first half.
But United couldn’t see it out as Ryan Yates headed home from a corner in injury time, denying the Blades what could be two crucial points against a play-off rival in the race for the top six.
Here’s how our man rated the Blades’ players on an evening of frustration and disappointment at Bramall Lane.
1. Wes Foderingham 7.5
Made a good early save to deny Johnson and an even better one to keep out Zinckernagel after more sloppy play from United. Then did it again from the penalty spot to keep out Johnson's poor effort Photo: George Wood
2. Femi Seriki 5
Making his full league debut with George Baldock injured, Seriki was full of endeavour but in reality, not much went right for him. Replaced by the left-footed Osborn in the second half Photo: Andrew Yates
3. Ben Davies 6
Returned at right centre-half to bring a bit of experience next to Seriki, and a brave header at the back post prevented his near-namesake Davis having a tap-in at the back post. Did well again to prevent Davis from testing Foderingham after Fleck's poor header back Photo: Darren Staples
4. John Egan 5
Caused a bit of panic early on when his loose pass surrendered possession, and Foderingham had to save from Johnson. Did it again and was indebted to his goalkeeper for bailing him out as Zinckernagel looked to poke home. Did well with a recovery tackle in the second half to prevent Johnson bearing down on goal Photo: Darren Staples