Manager Jack Lester was left to reflect on the award of penalty late on the game which was converted by Mitch Rose, sending the Spireites to a 1-0 defeat at Grimsby Town.
Sid Nelson was ruled to have handled inside the area following a long throw into the area.
Speaking to iFollow after the game at Blundell Park, Lester said: “In a game this big you have got to make sure those sort of decisions are right. It hits him on the shoulder and he has given a penalty.
“The referee is looking through bodies so I am not sure he can see clearly.
“For the throw-in, Alex Whitmore had gone off injured so we were a man down in the box. However, Sid has got nobody anywhere near him so perhaps should move his feet better and get his chest behind it.
“I am not saying we were good enough to win the game but we certainly should not have lost it.
"I never felt we were under threat. There was a bit of a flurry when they had a few shots go over the bar."
Lester was frustrated with his side's failure to capitalise on the opportunties they were presented with.
“We had good chances at 0-0 in the first half to get ourselves in front and you have got to take them in the big games," he said.
“I thought Andy Kellett had a couple of good chances stepping in on his left foot. They are chances in training that he scores comfortably. They were big chances.
“The crowd here can go either way and we needed to score first and gain the momentum. We missed too many chances and then we got done on a bad decision.”
Explaining his decision to introduce Chris O’Grady in the latter stages of the match, Lester commented: “We thought we could go and win it and we put another man on up the pitch.
“I thought Andy Kellett had a couple of good chances stepping in on his left foot. They are chances in training that he scores comfortably. They were big chances.”
There are seven games remaining for the Spireites to try and secure their League Two status - starting with Tuesday night's trip to Morecambe - and Lester insists it is important to stay positive.
“There are games remaining but we have to go and win them," he added. "We keep talking about being positive and I am a big believer in that.
“We have to move on very quickly. It is a very difficult situation but we have to go to Morecambe and win.”