Philippe Clement has vowed he would 'quit his job' if he genuinely felt a referee was biased.

Willie Collum will take charge of Rangers' Scottish Cup tie against Ayr United tomorrow evening.

It will be the experienced official's first game involving the Ibrox club since the penalty controversy that surrounded Celtic's 2-1 win over Rangers on December 30.

Rangers were left reeling after VAR, operated by Collum that day, decided to instruct Nick Walsh to wave play on after Alistair Johnson's handball inside Celtic's area.

It was later revealed, from the Scottish FA's point of view, that Abdallah Sima had been flagged for offside in the build-up to the goal.

However, Rangers chiefs met for talks with the SFA's head of refereeing Crawford Allan.

They then lodged an official complaint to the SFA & SPFL by requesting that Collum should not be involved in officiating any future Rangers fixtures.

Of course, this was thrown out by the governing bodies, as they stuck by the referee. 

And he's due to return to Ibrox tomorrow for the first time since the Old Firm derby incident, as Scott Brown takes his Ayr United side to Glasgow.

Clement has backed Collum, insisting he has no issues with the SFA's decision to appoint him to a Rangers game.

READ MORE: Tom Lawrence to miss Rangers' clash vs Ayr as a 'precaution'

He said: "I am happy to be honest. When there is one moment that I would think a referee is not neutral I would directly quit my job. So I am happy we can leave the past behind us."

The Belgian then revealed he played no part in the request made by Rangers over Collum.

He added: "No. That is something for in the club and we've talked about it. But that will happen in the future, yes."