John Sheridan felt his Chesterfield side deserved a share of the spoils after slipping to a 1-0 defeat at Rotherham.
Adam Le Fondre's ninth of the season, a sublime lob, gave the Millers victory and inflicted a first league defeat of the season for the Spireites.
"It was quite an even game, but the most disappointing thing was the manner of the goal," Sheridan said. "It was a shocking goal to concede. Just players switching off. The ball went out of play and they should have got a grip and got themselves organised.
"We had one or two chances and I thought we deserved something out of the game.
"We knew what we were going to get with Rotherham. They are big and strong. The last ten minutes of the first half and then again in the second we had a little go, but unfortunately we didn't get anything out of the game.
"There wasn't a lot between the sides and I think a draw would have been a fairer result, but I am very very disappointed about the goal."