Danny Wilson was unhappy his side were not awarded a second-half penalty after the Blades were held to a 0-0 draw by MK Dons.
Wilson was frustrated by referee Carl Boyeson's refusal to point to the spot when winger Ryan Flynn went down in the box in the latter stages at Bramall Lane.
"I thought we played really well, both teams had a go and it was nip and tuck," said Wilson.
"I thought we took control of it in the second half and we dominated for large, large periods. I think they only really had one half-chance when the boy went through, but he's gone down and he's rightly booked for simulation.
"And then the other side of it, we've got Ryan. We've looked at it I don't know how many times and it's a stonewall penalty.
"You look at the decision referees give sometimes; we had a game last week where we complained about the referee because of his inconsistency and today was exactly the same.
"We won last week, we didn't win this week but I thought overall it was a good game for large parts even though it was nil-nil.
"The few chances that did fall our way, we didn't quite get the rub of the green."