Exeter manager Paul Tisdale admitted his side were not good enough as they crashed to their fourth home defeat on Saturday.
Chesterfield's Chris Atkinson headed the only goal of the League Two game at St James Park after 31 minutes. The Spireites were worthy winners and created the better chances and it took 79 minutes before Exeter registered their first shot on target.
"It wasn't good enough" Tisdale said. "I am not going to elaborate on why that was, but it wasn't a good enough performance. It was a bit confused and our direction wasn't cohesive. We didn't have a common direction to our play.
"It was a very disappointing game for us and there are certainly some challenges ahead. It wasn't a good day for us. We came close at the end but they are entitled to throw themselves at things. I am not going to bemoan that because we were not good enough with our play.
"Regardless of whether we had got an equalising goal, it wasn't acceptable for what I hope to be a successful team. I have to understand and give us some better direction at home.
"I know it has to be improved and we will do our very best to do it."
