Livingston manager Gary Holt reckons Don Robertson blundered in not sending off Filip Helander - and revealed the referee agreed with him.
The Rangers defender scythed down Lyndon Dykes from behind in his side's 1-0 win and even Steven Gerrard admitted he could have walked.
Holt was unhappy at the Helander call but insisted the flashpoint wasn’t to blame for his side’s cup exit.
However he revealed ref Robertson admitted he made a mistake in failing to dig out the red card.
Holt said: “Yeah. It didn’t help us but I don’t think it cost us the game. We still created enough chances.
“You do want the fine lines and wee breaks to go your way against the bigger teams. It didn’t go our way but it is one of those things.
“I think the referee said he had look and said it was a red card after the game.
"He’s apologised to the players and sometimes you have to accept he is man enough to do that. I think he said to the players walking off.
“But attacking and defending we need to be better. We need to get in and score those chances we are creating. You put in all that effort but at the end we are out of the cup.
“It’s a Catch 22 because I thought to a man they are excellent. I can't fault their effort and desire, it is about that belief to go on and do it."
