Huddersfield manager Mark Robins believes Addicks midfielder Dale Stephens should have been sent off for a high tackle which put Adam Hammill out of the game in their 1-0 FA Cup defeat to Charlton.
Stephens escaped with a booking after a 28th-minute challenge which sparked an angry response from players on both sides as Charlton went on to claim a 1-0 victory in the fourth round.
Robins said: "I think it was a red card but the referee has a decision to make.
"I have seen the photograph and both his feet were off the ground and it doesn't make good watching.
"At the end of the day we are out of the Cup and you can't control what the referee does."
Robins said there were some other "tough challenges" in the game and added: "I could moan all day long but it sounds like sour grapes so I will desist."
Stephens was lucky not to have been sent off for the high tackle on Hammill, who limped off the field minutes later.
Players from both sides reacted and referee Stuart Attwell booked Stephens and Michael Morrison for Charlton and Anthony Gerrard for Town.
Charlton manager Chris Powell said the referee's decision was a 50-50 one.
"It was a tackle Stuart saw and he has to make an instant decision," said Powell.
"He sees it as a yellow and sometimes those decisions go for you and sometimes they don't. We have had times this season when there was a red.
"Emotions were running quite high and I don't want to see any dangerous tackles."
Huddersfield had chances to win the game in the first half but Oliver Norwood, Oscar Gobern and Danny Ward were wasteful.
Keeper Ben Alnwick pulled off a great save from Ward and Powell said: "We rode our luck at times and our keeper made a point blank save to keep us in it.
"We just kept chipping away and got our just rewards."
Powell said he hoped his side's cup form could provide a boost in the Championship after Charlton slipped into the bottom three despite not playing.
Powell added: "We haven't done ourselves justice in the league and we have to do better.
"Winning games in the cup - at Oxford and Huddersfield - should give us more confidence."
Former Town loanee Simon Church scored the only goal in the 54th minute with a good finish beyond Alex Smithies into the far corner.
Powell said: "Simon hasn't scored for a while but he will always get in good areas. It was a well-worked goal and a great finish."
Robins said Hammill going off "seemed to burst the balloon" and added: "It was a poor goal to concede and we have to hold our hands up.
"We are out of the competition because it was an error strewn game and we did not take our chances.
"The disappointment to me was that we stopped probing and passing and didn't have enough guile."