Andy Farrell’s men travel to Edinburgh with Grand Slam aspirations still in tact thanks to bonus-points wins over Wales, France and Italy.
The world’s top-ranked nation have dominated matches against the Scots during the past decade, winning 11 of the past 12 meetings.
But Gregor Townsend’s side have been a far tougher proposition in this year’s tournament – beating England and Wales before defeat in France – and are bidding for a first Triple Crown since the 1990 Five Nations to keep themselves in title contention.
Fly-half Sexton, who sat out the round-three win in Rome due to a groin issue sustained against France, believes Ireland are “privileged” to be vying for a clean sweep and is braced for the greatest test of the championship so far.
“We don’t consider ourselves favourites, we don’t even talk about that,” he said. “We think it’s going to be an incredibly tough game.
“They’re probably the best Scottish team – maybe not of all time because there are Scottish teams that have gone on to win championships and stuff – but definitely the best Scottish team we’ve played against.
“Probably since the Six Nations started, it’s the best Scottish team. It will be a really, really tough game and it will probably be our toughest of the championship so far.”
Ireland set aside the absence of a host of star men at Stadio Olimpico, including their influential skipper, to remain as the competition’s pacesetters.
Sexton, who confirmed he is “good to go” this weekend, previously won a Grand Slam in 2018 – the third Six Nations triumph of his distinguished career.
The 37-year-old believes Scottish hope of ending a 33-year Triple Crown drought adds an extra edge to a tricky away trip.
“Every team comes into this competition wanting to win a Grand Slam, wanting to win a championship and that’s why it’s so important to get off to a good start because it keeps everything alive,” he said.
“We still have them in our grasp so we obviously talk about it and make sure that we deal with the pressure that comes with that but it’s a privileged position to be going for it.”
Speaking of Scotland’s Triple Crown aspirations, he continued: “It’s something that we’re going to have to acknowledge because it’s going to make for a very special atmosphere over there I’m sure – it always is a very special atmosphere even if there was nothing on the line.
“But it’s a huge game now with them going for a Triple Crown and still in the championship and us obviously in the championship and obviously wanting to try and win a Triple Crown ourselves.
“It’s a massive game, so it’s great to be a part of.”
Sexton could also achieve a personal milestone on Sunday as he is closing in on becoming the Six Nations’ all-time leading points scorer.
The Leinster man, who sits just seven championship points short of former international team-mate Ronan O’Gara’s record total of 557, insists collective glory tops individual achievement.
“It’s something that people say to you or you see it on social media,” he said. “Irish Rugby tagged me in something today, which I wasn’t too happy about!
“It’s there but I don’t think it’s going to add any pressure to me or anything like that. It’s not something I ever set out to do.
“I’d rather not score another point and win a championship, win a Grand Slam than get the points record. It doesn’t bother me too much. If it comes, fantastic, but it’s not something I lose sleep over.
“If the right decision is to go to the corner and pass on points, I will do that.
“But if you do it, it’s an amazing mark to do. Ronan obviously had an amazing career and even just to be in that same conversation is enough for me.”