Shaun Maloney insists Ryan Porteous didn't deserve to be sent off in Hibs' 3-1 defeat to Aberdeen.
Referee Alan Muir brandished a straight red when the 22-year-old scythed down Ross McCrorie in the box, with the Dons midfielder set to fire home.
The game was delicately poised at 1-1 when Porteous conceded the penalty which Lewis Ferguson fired home, before Vicente Besuijen added a third.
While Hibs boss Maloney agreed that he was a penalty, the 39-year-old questioned Muir's decision to send off Porteous and his call to award Aberdeen another spot kick earlier in the game.
"It was a very difficult one to take," Maloney admitted.
"I think in the last half hour, when you are down to 10 men, it slightly skews the feeling but the game changed on two decisions really.
"I think, for sure, we can play better but the decisions unfortunately the referee got incorrect but that is football.
"For the first penalty, the ball hits Rocky's knee first before it hits his arm which, going by the rules, means it should not be a penalty.
"It was definitely a penalty with Ryan but he made a genuine attempt to play the ball so he should not have been red carded.
"The two decisions completely changed the game."
Maloney admitted that the Easter Road side would likely appeal Porteous' red card in the hope of overturning his suspension.
He added: "At the moment I think we’ll appeal the red card.
"We’ll look at it on Monday but for me it was incorrect, he’s gone for the ball.
"Definite penalty, but the rules are that he shouldn’t send him off.
"It’s disappointing because it had a big effect on the game."
