Warning: Contains strong language

Aberdeen boss Derek McInnes says he was sent off during his side's Scottish Cup semi-final defeat for gesturing to Celtic fans singing a sectarian song he has had aimed at him "a hundred times".

McInnes followed assistant Tony Docherty - and two of his players - in being dismissed during the 3-0 defeat.

Celtic fans were heard chanting external-link that McInnes is a "sad orange bastard".

When asked if he was sent to the stand after reacting to sectarian abuse, McInnes said "aye".

The former Rangers player added: "I had let it go the first time but I shouldn't react and I'll take my punishment. I was wrong to do so, I should be better than that."

"I've heard that song a hundred times aimed at me so I think frustration from the game has played a part. It'll be interesting to see if everybody gets punished."

Speaking to BBC Scotland, the Aberdeen manager said he thought a warning from fourth official Nick Walsh would have sufficed.

"He's obviously deemed it serious enough to bring the referee over," he added. "I accept that, I'll apologise for that and any punishment going my way, I'll take it on the chin."

Ball red card was 'harsh'

The semi-final was goalless when Dominic Ball was sent off for a second booking after an aerial challenge on Celtic's Ryan Christie, who left the field on a stretcher after a lengthy stoppage.

James Forrest then put Celtic ahead and Aberdeen's Lewis Ferguson was dismissed for a challenge on Tom Rogic shortly before the Australian scored the third goal.

But McInnes questioned both of Ball's bookings, liking the aerial challenge to one by Celtic's Dedryck Boyata on Gary Mackay-Steven during Aberdeen's 1-0 League Cup final defeat in December.

"The sending-off changes everything, absolutely everything," McInnes said. "Any time you go down to 10 men against a good team like Celtic, I think it is pivotal.

"The first challenge, his first foul in the game, Jonny Hayes has actually kicked the ball out the park. The second one, it's a difficult one. I didn't see a flailing arm or an elbow, I just think it's a clash of heads.

"It's disappointing that for those two offences that Dom Ball then gets sent off. I think it's extremely harsh."

'Indiscipline unacceptable' - analysis

Former Aberdeen captain & manager Willie Miller

Dominic Ball has thrown his left leg and taken the player, so he's deserved that yellow card. You're then walking a tightrope. When he sees that challenge on, he should just not go for it.

I think Derek deserves the support from the board. But two players being sent off and the manager and assistant being sent to the stand, is unacceptable. That is worth a conversation between chairman and manager about the lack of discipline that Aberdeen showed in the second half. It's not acceptable.