Gillingham manager Martin Allen saw his side go top of League Two after their 1-1 draw against Chesterfield but then declared the performance was the biggest disappointment of the season so far.
Managerless Chesterfield took the lead through Craig Westcarr's early strike only for Danny Kedwell to equalise in the first half.
Despite piling on the pressure and Westcarr being sent off in injury time, Gillingham could not find a winner to end the Kent side's 100 per cent league record and leave Allen frustrated.
He said: "The only knock they've all had this season is the fact they haven't played as well as they can. There are no physical injuries, but I think everyone will feel we could've done better there.
"We didn't express ourselves and play the good football that we know we can play. There wasn't enough good passing and they all have a tinge of disappointment.
"It's early days but it's still, after five games, quite an achievement to be top. We gave a good account of ourselves against Middlesbrough on Tuesday night, but I don't think we hit top form against Chesterfield.
Westcarr was sent off in injury for a second bookable offence for kicking the ball away although he claimed he did not hear the whistle.
"When you're going through one-on-one and it's in the last minute of the game, you're always going to have a shot," said Westcarr.
"Obviously I've put it wide and before I knew the ref was running towards me and I was thinking, 'What's going on here'.
"He wasn't even going to send me off, but he realised I had already been booked so he showed me a red card. It didn't really make sense. I'm very pleased with the performance and I'm glad we can come to places like this and match them."