Margreitter's foul was a red card offence for sure after Murphy had left him for dead but I'd say the ref otherwise did OK and Chesterfield were certainly the better side. United had a golden chance to take advantage of the young lad coming on to play in goal after Tommy Lee was sent off but failed to take advantage till it was too late. Jamal made a big difference but the Blades' midfield men were outplayed by the combination of Johnson, Morsy, Ryan and Roberts, plus O'Shea before he took one for the team. Jimmy Ryan is everything a playmaker should be; he rarely wasted a pass and scored a belting goal.
Jones' absurd theatricals after Higdon took him out were pretty shoddy but it was a crude foul regardless, and I thought the ref took revenge on Jones by booking him later when he hadn't done anything wrong, as well as giving the free kick from which Collins scored, but 3-3 would have been a travesty to be fair. Chesterfield look good enough for the play-offs with such a strong squad to choose from, whereas the Blades, in all honesty, currently don't.