Davie Weir believes his former club Rangers have their work cut out to catch up with Celtic whilst Brendan Rodgers is in charge of the Hoops.

Former Ibrox captain Weir was assistant manager to Mark Warburton two years ago when the Light Blues secured their last triumph in an Old Firm derby by beating Celtic on penalties in the Scottish Cup semi-finals.

Rodgers, who replaced Ronny Delia in the summer that followed, is yet to taste defeat in the derby - winning seven of his nine matches against Rangers.

Warburton, Pedro Caixinha and Graeme Murty have failed to end the Hoops' period of derby dominance over the last two seasons.

Weir reckons Rangers face a "really difficult" task to overcome Rodgers' side, regardless of who is in charge at Ibrox next season.

Speaking at a William Hill media event at Hampden Park ahead of Sunday's Scottish Cup semi-final between the Old Firm rivals, he said: "I think it will be really difficult. He (Rodgers) is a top manager. He has a method in regards what he does.

"He has the respect of the players, the club, everybody and he is setting the bar high.

"Celtic's managerial appointment was really good. There was obviously a lot of thought and planning went into it.

"They picked the right man at the right time and he has shown their faith was right."

Current Ibrox boss Murty was installed as boss until the end of the season, with Rangers yet to decide whether to offer the former Scotland international a longer-term stay in the hotseat.

Weir believes a semi-final win would offer a great boost to his former colleague's chances of securing the job.

He added: "Graeme has done really well.

"We brought him in as an under-20s coach from under-18 football at Norwich, so the jump has been really quick and really far in a short period of time.

"He has coped with that really well. He has been put in a difficult situation and he has handled it well.

"Rangers are competitive, they are fighting for second place (in the Ladbrokes Premiership) so that will be a success this season and they are in the semi-final of the cup.

"Longer term, is he right man for the job? Time will tell but winning the semi-final and finishing second in the league will certainly help that.

"I am sure he won't be thinking about his long-term future but for Rangers it is important to win the semi-final.

"It has been a long time since Rangers have beat Celtic.

"So that must be a great motivation, whether it is for Graeme's future or anyone's future."