Nathaniel Mendez-Laing climbed off the bench to score for the second time this season as the Grecians suffered yet another early cup exit.
Tisdale said: "Naturally I'm disappointed not to have a cup run again.
"We put a lot of preparation into the game and applied ourselves well. We played very competently and built our performance nicely during the game.
"We had a good spell prior to Peterborough going ahead and what I thought was a strong penalty shout when Danny was pulled to the ground.
"As well as we played, you have to pack a punch to win games and Peterborough did that."
- Sports & Recreation
- Danny Coles
- Hogan Ephraim
- Britt Assombalonga