Former Rangers boss Alex McLeish has told the current Ibrox team to copy the example set by Bradford and Middlesbrough as they set out to stun Celtic.
The Genk boss (right) - who won eight of the 20 Old Firm games he bossed between 2001 and 2006 - said: "Normally Celtic should win because of the difference in quality. But it's a cup tie and an Old Firm game. Rangers will probably raise their game big time.
"We've seen the big FA Cup upsets in England over the weekend. There is no reason why Rangers can't do that.
"You have to believe. There is no point going out onto the pitch thinking: 'I'm intimidated. I'm overawed by this.'
"For this game, I'd like to think they will step up. If Rangers get everything right tactically, they can upset Celtic."
Meanwhile, former Rangers midfielder Gennaro Gattuso insists he would love to return to Ibrox as boss - but only once the club's boardroom battle has been settled.