Shaun Miller and Harry Maguire had put the Blades in control after half an hour, but the visitors raced back and turned the game around with goals from Mark Ellis, Mathias Pogba and Chuks Aneke.
Nick Blackman then struck the equaliser for the Blades in the 51st minute.
The Railwaymen manager said: “We showed great character and our lads didn’t know they were beaten.
“I felt we might just win a game, but neither team could hold onto a lead, the game’s wide open and it could have gone either way at the end.
“It was a good game, great exciting game for the supporters. I’m sure ours will go home a bit happier. It was great point for us in the end.”
A goal apiece from James Tomkins and Luka Milivojevic handed Crystal Palace a crucial 2-0 win over Huddersfield at the John Smith's Stadium on Saturday evening.
Manchester United bounced back from their Champions League exit as they beat Brighton 2-0 at Old Trafford on Saturday night to reach the FA Cup semi-finals.
Tottenham reached the FA Cup semi-finals after they cruised to a 3-0 victory over Swansea in their quarter-final clash at the Liberty Stadium on Saturday.