Why Scotland have made Six Nations changes and who will have last word before facing Ireland

Both locks were invalided out of the stunning 50-40 triumph over France last weekend, a match which means Scotland go into the final weekend of the Six Nations Championship in the giddy position of joint top.

It’s uncharted territory for the Scots who have never finished in the top two since the tournament was expanded to include Italy in 2000.

The campaign ends on Saturday, with Townsend’s side taking on Ireland at the Aviva Stadium at 2.10pm and France hosting England in Paris at 8.10pm.

The Scots are level with the French on 16 points at the top of the standings but Fabien Galthie’s side are odds-on favourites to win the title. Their points differential of +79 is 58 points better than Scotland’s and 63 better than third-placed Ireland. But a win for the Scots in Dublin can pile the pressure on France.

With Cummings and Brown absent, Townsend has turned to Grant Gilchrist and Max Williamson as his second row pairing.

Gilchrist, 35, is the senior statesman in the squad, a former Scotland captain who made his international debut back in 2013. It’s been an eventful Six Nations campaign for the Edinburgh lock who was picked to start in the opening game against Italy then promptly dropped after the disappointing defeat in Rome.

He returned to the squad for the round three and four clashes with Wales and France, coming off the bench in both victories. He now finds himself back in the starting line-up and will win his 88th cap in Dublin, breaking Scott Murray’s all-time Scottish international appearance record for a lock forward.

Williamson, by contrast, will be making just the second Six Nations start of his career. The 23-year-old began the round three game against Wales in Cardiff but struggled during a difficult first half for the Scots and was replaced after 34 minutes.

Townsend has no qualms about trusting him in Dublin and believes the Glasgow Warriors lock can seize his chance.

“Straight away, he said he didn't play as well as he could have and should have [against Wales], but we've seen enough from Max in other games,” said the coach. “And we've seen enough in training, how he responded in training. I love players getting second opportunities.”

Why Scotland have brought back Zander Fagerson

The third change Townsend has made to his starting XV is bringing Zander Fagerson back. The Glasgow tighthead began on the bench against France and came on for D’arcy Rae just before half-time. The pair will swap roles in Dublin, with Rae on the bench.

“Zander's impact in the game was outstanding,” said Townsend. “That period where we took the game away from France, Zander was involved a lot in the carries and the contact clears. I think his carry set up Ben White's try in the second half. He's been an outstanding player for us. We feel he's better starting this week, fresh too. He's only played 41 minutes in the last two weeks, so it gives us an opportunity to really go at Ireland around the contact area.

“We know D’arcy's in a good place too. He was very good in contact, he's trained really well this week. To get that performance out of him, we know he can make a big difference off the bench too.”

The rest of the starting side is the same as last weekend, no surprise given the way they dismantled France, leading 47-14 at one point before a late French rally. Townsend has made significant changes on the bench, however, with Alex Craig, Magnus Bradbury and Kyle Rowe all included for the first time in this championship. Josh Bayliss and Freddy Douglas drop out.

Craig, the six-times capped Glasgow forward, will cover the second row while Edinburgh No 8 Bradbury gives Townsend an abrasive back-row option in what is sure to be a hugely physical game. Rowe, meanwhile, has been in fine form for Glasgow and will cover the back three as the coach reverts to a five-three blend among his replacements.

“We feel it'll be a different game to the French game,” said Townsend. “We think it'll be close to the contact area, just with the way Ireland defend, also the way they attack. Magnus brings us that front foot, ball-carry. He's physical in defence too. He won two jackals in the last game he played for Edinburgh, he can compete post-tackle.

“We feel five-three is right this week given we had a few injuries in the backline last week. Also, the form of Kyle Rowe that we've been seeing in training and in his last game for Glasgow was outstanding.”

Scotland ended the game against France with flanker Rory Darge playing at centre after losing Kyle Steyn and Huw Jones to injury but, happily, both have recovered to start in Dublin in what is the national side’s biggest game in a generation.

As well as the title being on the line, the match at the Aviva Stadium is a straight shoot-out for the Triple Crown, an honour Scotland have not won since 1990.

Townsend was deliberately playing down the size of the occasion as he spoke to the media on Thursday but he feels the belief in the squad is growing on the back of successive victories over England, Wales and France. He said he would let captain Sione Tuipulotu set the emotional tone in the changing room and believes the squad are in a good place.

“You get a feel for where they are on the morning in the game, and I don't think we'll be needing motivated this week,” he said. “I think it's about just saying that you believe in them, which I firmly do, and can't wait to see them play.”

The coach claimed he had not given winning the title much thought and had not spoken to the players about the historical aspect of what victory might mean. Instead, they have been sticking to training as well as possible so they can build on what was a superlative performance last weekend against France.

“The rest should take care of itself, and the players know that if they put that effort in, and they drive the physicality, then you'll get your rewards,” said Townsend.