Nick Carle's injury time volley rescued a point for Crystal Palace.
Sheffield United looked to have won the game through James Beattie who scored a late penalty having been hauled to the ground by Patrick McCarthy.
But Carle volleyed past Paddy Kenny from 12-yards out to give the visitors a share of the spoils.
The Blades had taken a first half lead through Nathan Dyer who found the net from the edge of the box before Patrick McCarthy converted John Oster's corner.
Sheffield United manager Kevin Blackwell:
"It's a bit frustrating to say the least.
"Where he's got the time from I don't know but you can't complain about referees, can you?
"We knew it was going to be tough and there was all the stuff about Neil Warnock coming back but we dealt with that and looked as though we were going to win.
"We should have been smart and kept the ball in the corner at the end. It's a cruel game and I'm sick, to be honest."
Crystal Palace manager Neil Warnock:
"It was no more than we deserved, we hit the bar and came close on a few occasions so I'm delighted not to have lost.
"I don't think it was a penalty so I think a point was a fair result.
"I'm proud of them and we never gave in and I'm pleased the game was not settled on that late penalty decision.
"It was a great goal late on and it shows our spirit to keep going."
Sheff Utd: Kenny, Morgan, Kilgallon, Ehiogu, Naughton, Montgomery, Howard (Halford 90), Quinn, Dyer (Stokes 72), Beattie, Webber (Cotterill 77).
Subs Not Used: Bennett, Sharp.
Booked: Montgomery, Morgan, Kilgallon.
Goals: Dyer 41, Beattie 88 pen.
Crystal Palace: Speroni, Clyne, Fonte, McCarthy, Hill, Oster (Butterfield 79), Derry, Carle, Ifill (Moses 56), Kuqi (Lee 46), Scannell.
Subs Not Used: Lawrence, Griffit.
Booked: Derry, Kuqi, Hill.
Goals: McCarthy 47, Carle 90.
Att: 23,045
Ref: Paul Taylor (Hertfordshire).
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