Derek McInnes became the fourth Aberdeen man to be sent off as the Dons lost the plot against Celtic.
The Pittodrie boss – who had already seen Dom Ball and Lewis Ferguson red-carded – joined his assistant Tony Docherty in the Hampden stands after reacting to sectarian chanting from Celtic fans.
McInnes was spotted remonstrating with assistant referee Nick Walsh in the 73rd-minute mark and was ordered off.
He joined midfielder Ferguson away from the pitch after the Dons midfielder committed a shocking challenge on Tom Rogic.
Ferguson went in two-footed, while of the ground, on the Aussie for which Celtic were awarded a free-kick just outside the box.
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Rogic slammed home the set-piece to put Celtic 3-0 up to book their place in the Scottish Cup Final.
McInnes seemed furious with the treatment from Hoops fans and after Walsh had relayed the incident to Craig Thomson, the referee ordered him to the stands. The Dons boss urged Thomson to come and speak to him so he could explain what happened but the plea fell on deaf ears.
As the Dons boss walked off the tunnel he continued to be the subject of the bigoted chant "sad Orange b*****d" from Celtic supporters.
