Harry Kewell feels the decision to award a penalty against Jamie Turley cost Notts the result at MK Dons on Tuesday night.
The centre-half was given his marching orders following a soft-looking coming together with Rhys Healey.
The hosts went on to come from behind to win 2-1 and manager Kewell feels the game rested on the call made by Michael Salisbury.
“I’ve seen it from several angles and just don’t understand how he has awarded a penalty,” said the manager.
“No one else thinks it was a penalty, even the fourth official and MK’s manager Paul Tisdale, and that decision has cost us the points.
“Paul has been in the game for a long time and he admitted we were hard done by, so we will be appealing the red card and we fully expect Jamie to be available on Saturday.”
Despite the result, the Australian hailed the performance as one of the best since he took the reins.
“We were perfect in the first half and even with 10 men we were absolutely brilliant,” he said.
“I can’t fault the players at all because I feel they were all excellent. They came to a great stadium to face a talented side and didn’t give them a sniff until after the red card.
“We’ve had positive spells during past matches but today I could not have asked for more and if we play like that in future we will win more games than we lose.”
Kewell believes attention must immediately switch to Saturday’s clash with Swindon at Meadow Lane.
He said: “There’s nothing we can do about it now so we have to forget it and move on.
“We have to rid ourselves of the frustration that we are currently feeling and ensure we have clear heads going into the game against Swindon.
“We will pick ourselves up and go again. Today we were excellent and I hope to see that level of performance again on Saturday.”