CELTIC great Stiliyan Petrov believes the Parkhead club are so far ahead of their Scottish rivals they are capable of completing the treble for the next THREE YEARS.

But Petrov fears a lack of serious competition domestically could lead to Brendan Rodgers and his top players moving on seek a greater challenge down south or abroad.

The Glasgow giants have the chance to complete the second leg of a clean sweep of domestic trophies on Sunday when they face Rangers in a Ladbrokes Premiership game at home.

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If they beat their city rivals for the fourth time this term and finally sew up their seventh consecutive Scottish title they will then have the chance to make history.

A win over top flight rivals Motherwell in the William Hill Scottish Cup final at Hampden on May 19 would see Celtic become the first club to complete back-to-back trebles in this country.

However, former Bulgarian internationalist Petrov has predicted they can win the League Cup, League and Scottish Cup five years running.

“I think Celtic have got a chance to win the treble again next season as well,” said Petrov, who was back in Scotland last week to play in the John Hartson Charity Foundation golf day at Trump Turnberry.

“If Rangers keeps going the same way, they have a chance to do it over the next three years. We predicted it a year ago and they are going to do it strongly. I would say that it is sad in one way because, if we see that happen, Scottish football will lose its identity.

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“The advertising in Scottish football is Celtic vs Rangers. I come from a different country and every time the game came up, I’d watch it.

“The build-up, the excitement, the electricity. Everything. If that is lost, it would be very sad for Scottish football. I’m saying that as an outsider.”

Petrov reckons that could hasten the departure of Rodgers – who has been installed as one of the favourites to replace Arsene Wenger at Arsenal at the end of the season – and players like Moussa Dembele, Tom Rogic and Kieran Tierney.

The 38-year-old, who helped Celtic reach the UEFA Cup final in 2003, feels his old club may struggle to attract decent players to replace them if they continue to dominate in Scotland.

“Celtic have a lot of young, exciting players,” he said. “These players would like to improve and be challenged. If they are not challenged here, if they don’t have someone to push them, then they will go. Can you blame them? No.

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“If someone comes for Moussa Dembele and he is not being challenged here then he will move on.

“People talk about Henrik Larsson, but he explained why he stayed. The push, the build-up, the physicality – everything about that Celtic v Rangers and how it was shown around the world – kept him here.

“If you don’t have that, how are you going to attract the good players to come to Scotland?”

Petrov continued: “Don’t get me wrong, it’s great to be a Celtic player at the moment because they are making history. You can only play what is put in front of you and they have a chance to do two trebles on the bounce.

“That is something that has never been done before so these players will be in the history books at Celtic. But they haven’t been challenged. And these players are good enough that they need to be challenged.”