The striker won the ball before his trailing leg caught Ajer on the follow-through.

McInnes said: "I have watched it 20 times and Cosgrove has won the ball cleanly.

"If he goes in at speed and hits the player at any point then you could understand maybe the referee sending him off. When you go in at speed like that you have got to make sure you get the ball and 100 per cent it's a brilliant tackle.

"He probably doesn't need to go in as quick as he does but he has won the ball cleanly.

"And then you've got big Ajer winking at him and laughing at him lying on the ground. There's nothing wrong with the boy. The boy carries on, I didn't see anything wrong with him, he is running about.

"If Sam Cosgrove has hit Ajer going at that speed, Ajer is hurt, and the boy is clearly not hurt. It's a brilliant tackle."

Celtic skipper Scott Brown ran 20 yards to remonstrate with Cosgrove but McInnes refused to comment on whether the reaction had influenced the referee.

But the Dons boss claimed his Celtic counterpart Neil Lennon agreed with his assessment on the tackle.

"I just spoke to Lenny, and I know it's easy for a winning manager to say it, he says 'no way it's a red card'," McInnes said. "Lenny thinks we have been harshly treated there, I think we have been harshly treated.

"Celtic are 2-1 up, they are a strong team, they are going well. It's not to say it changes the course of the result but it certainly gives us a better chance if Cosgrove stays on the pitch."

Lennon left assistant John Kennedy to speak to the media and the former Celtic defender felt Cosgrove had been taking a risk with his challenge.

"I don't think he fully catches him, he just nicks him," Kennedy said.

"But in the modern game when you fly in at that speed, and you leave the ground, and there is a form of recklessness about it, you give the referee a decision to make and in his eyes it was a red card. So that's up to him."

Celtic had 28 efforts at goal to Aberdeen's two and Kennedy always felt the winner was coming.

"It was another great performance," he said. "We would have liked to have put the game to bed earlier. But our general performance, the chances we created and the way we played, was terrific."