Scotland can record one of their greatest ever results by beating Ireland at Murrayfield on Sunday, says former captain Greig Laidlaw.
The Scots must win to have any hope of pipping the Irish to the Six Nations title after losing in France.
Scotland have never beaten a team at number one in the world since the rankings were introduced in 2003.
"It would be right up there, one of the best ever victories," Laidlaw told the BBC Scotland Rugby Podcast.
"Have we ever beaten the current ranked number one team in the world? I wouldn't have thought so. That's the task at hand.
"But if Scotland play to their full potential I definitely think they can win. Is it going to be easy? Certainly not. Is it going to be a big score? No.
"We certainly can be in the fight and we've got a bit of stardust sprinkled throughout the team that can break anybody down."
Scotland opened their Six Nations campaign with back-to-back wins over England and Wales before going down in Paris.
Having beaten Wales, France and Italy, Ireland are on track to underline their status as the world's top side with a Grand Slam. They have not lost to Scotland since 2017, when Laidlaw kicked the home side to victory at Murrayfield.
Despite going into the match as favourites, Laidlaw says head coach Andy Farrell will ensure complacency does not creep into the Irish camp.
"There is no chance Ireland will be coming over underestimating this Scottish team," said Laidlaw, who toured New Zealand with the British and Irish Lions in 2017 when Farrell was defence coach.
"He'll have them revved up like they were against France. They'll understand the challenge and it is going to be a challenge, make no bones about it.
"Do I think Scotland can win? I do. They're going to have to get everything absolutely right otherwise it's going to be a tough ask because they're playing a team with excellent players who are very well coached and they're high on confidence.
"Anytime you come up against that it's going to be one of the biggest battles. They're not the number one ranked team in the world for no reason."
Listen to the BBC Scotland rugby podcast with Greig Laidlaw from 20:00 GMT on Tuesday here
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