Chesterfield boss Danny Wilson said he was "disgusted" with referee Lee Swabey's decision to send off Gary Liddle in their 1-1 draw with League One bottom club Colchester.
Liddle was shown a straight red card for a challenge on defender Kane Vincent-Young after just 18 minutes, leaving the Spireites to play most of the contest with 10 men.
The visitors ended up claiming a point, with substitute Lee Novak's 73rd-minute penalty cancelling out Macauley Bonne's opener moments before, but while Wilson was pleased with his side's performance, he was far from happy with the dismissal.
Wilson said: "I'm disgusted with the decision (to send off Liddle).
"It's a hard tackle but a clean tackle - he gets the ball cleanly.
"Can we not tackle nowadays? The referee was in a perfect position and his quick reactions were wrong.
"It affected the game and gave them a great advantage which they didn't take in fairness, because I felt we performed so well."
Wilson added: "We were given some really tough circumstances in which to play the game out in the early part of the game, but we came through it really well.
"I thought that our discipline was excellent and the work ethic from the boys was fantastic, in the second half in particular.
"They had a couple of efforts on goal but nothing really to talk about.
"I think overall, you can't take anything away from our performance particularly having had to go about our business a player down."
Colchester remain eight points adrift of safety and have not won in the league since mid-October.
U's boss Kevin Keen said: "I'm more than disappointed because when you play against 10 men for 70 minutes, we created enough chances but in the second half we weren't quite good enough.
"They made it tough for us and they changed their formation at half-time and gave us a few more problems going forward.
"But we had chances and George (Moncur) had a chance to win it for us near the end."
Chesterfield keeper Tommy Lee denied Chris Porter in a goalless first half, while Novak went close just after half-time.
Bonne converted substitute Drey Wright's low cross from close range to give Colchester a 69th-minute lead.
But Novak quickly equalised after being fouled by Richard Brindley in the area and Colchester keeper Elliot Parish denied Sylvan Ebanks-Blake before Lee foiled Moncur, as the spoils were shared.
Keen, whose side had lost their previous four matches in all competitions, added: "It was a great finish from Macauley Bonne and from Drey Wright's cross, it was two Academy graduates who made and scored the goal.
"Teams are more vulnerable when they've just scored a goal and our game management has got to be a lot better.
"It's mentally tough for us at the moment to get that win.
"But we'll keep going - we've stopped the run of defeats and we have to keep working hard and try and get that win on the board."
Source: PA
