Tavernier was penalised for a foul on Leigh Griffiths, but the right-back later insisted he got the ball and that the Celtic striker agrees with him.
Scott Sinclair tucked away the resulting spot-kick, adding to Callum McGregor’s 11th-minute opener and assuring the Scottish champions passage through to the final.
Collum gave the decision after a brief consultation with Don Robertson, the extra official behind the goal who had been the source of much controversy following his decision to award Ross County a penalty against Celtic last weekend.
Speaking to Rangers TV, Tavernier lamented the decision of the officials.
He said: “I thought it wasn’t a penalty, I thought I got the ball first.
“Griffiths thought it wasn’t a penalty when I spoke to him.
“It was just one of those decisions that the ref behind the goal’s given the penalty.
“It’s just one of those where it’s just been given and you can’t do anything about it.”