Tisdale's team had kept the Spireites at arms' length for most of the game until a late penalty lifted the home side up to second place in the League Two table.
Tisdale thought that was harsh on his players who had defended well and played with composure after a deflected free-kick by Matt Grimes had given them an 18th-minute lead.
After Sam Morsy was sent off for a two-footed tackle on Grimes, Tom Nichols hit the Chesterfield woodwork before Eoin Doyle tucked away a 78th-minute spot-kick after he was brought down by Danny Butterfield.
Exeter would still have won it but for a brilliant save by Tommy Lee from Scott Bennett, and Tisdale admitted: "It was a fantastic performance and a well deserved point but I'm very disappointed we didn't get three.
"On the run of the game, we had enough to get the three so although it might sound odd, I'm bitterly disappointed. We absorbed pressure and did it very well and we counter-attacked and created clear-cut chances.
"We got a goal from a deflected free-kick but if anyone thinks we were lucky they are doing us a disservice. Our season was probably summed up in the minute where Tom Nichol hit the inside of a post and then they get a penalty - which I thought was soft-ish."