Rochdale striker Bobby Grant scored the equaliser before seeing red as his side shared the spoils with Chesterfield.
Jay O'Shea gave the Spireites the lead in the second half, side-footing home from the left of the penalty area.
Grant sliced in a 25-yard curler to level the match - the first goal Dale have scored since Keith Hill returned as manager last month.
But the forward received a straight red with five minutes to go for a challenge on Sam Togwell in the centre circle.
Chesterfield appealed for a penalty late on, after Marc Richards was brought down in the box, but it was waved away by referee Andy Haines.
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Rochdale manager Keith Hill told BBC Radio Manchester:
"Chesterfield put us under a lot of pressure but we withstood that. There wasn't any real goalmouth action for both sides.
"I'm pleasantly surprised because, when you go a goal down, you don't know what reaction you'll get. It was a positive reaction and they showed a lot of courage out there.
"Even when we went down to 10 men, we looked as though we were capable of scoring."
Chesterfield manager Paul Cook told BBC Radio Sheffield:
"From taking the lead I really thought we would go on (and win).
"I felt we had the quality to open them up again and maybe get the second goal, obviously that never happened with Rochdale getting a fantastic equaliser.
"I felt it was a stonewall penalty and I never criticise referees, but it's not a hard decision.
"Then seconds later we could have got beat 2-1, so for me as a manager the biggest thing that disappoints me is the concentration levels, to concede that chance at that stage in the game, as we could have lost that game."