Manager Gary Caldwell was left to reflect on a much improved second-half display in last night's pre-season friendly at home to Rotherham United, which resulted in a 3-1 victory for the visitors.
A late consolation from Chris O'Grady capped off a promising performance in the second period after Chesterfield found themselves two goals down early on.
Caldwell was unhappy with his side's application before the break. He said: "The first half was unacceptable. I said that at half time.
"The first-half performance wasn't about tactics. It was about desire, hunger and being more aggressive, with and without the ball. We played with the hand brake on and didn't let that off until we made the changes."
Caldwell was hugely encouraged by the performance of his players after the interval. "In the second half, I thought we were excellent," he said. "We played on the front foot, played with aggression, started tackling, started running and got back into the game.
"If we'd scored in the spell that we had, then I think we would have got right back into the game and could have won it. I was delighted with the second-half performance and delighted to learn as much as I learned."
After O'Grady netted for the second game in a row at the Proact, Caldwell said: "His all-round display was outstanding. The team are lucky they have a centre forward they can look at who is a man that leads the line, runs about, does his fair share of work defensively, but then is also a real focal point for the team."
Caldwell was also impressed with two other summer signings - Louis Reed and Gozie Ugwu - who both came off the bench at half time and made a real impact. "I thought they were fantastic," he commented.
"Gozie won the ball back and caused a real threat down the right-hand side. Reed got on the ball like I know he can and started pulling the strings in midfield. That allowed the full-backs to get higher up the pitch, and we suddenly started playing in their half and caused them a lot of problems."
The Spireites have just one more pre-season game remaining, with Doncaster Rovers heading to the Proact on Saturday. Caldwell wants to see a repeat showing of their second-half performance agains the Millers. "We need to take it for a whole 90 minutes and get a result to give us confidence going into the start of the season," he added.