Finn Russell was still a teenager in Stirling when Johnny Sexton's shelving started creaking under the weight of all the trophies he was winning. By the time the Scot took his first steps into the Test arena, the Dubliner had won a Grand Slam, a series with the Lions, a European Challenge Cup, two Pro14 championships and three European Cups.

We're talking here about probably the most skilful player that Scotland has ever produced and almost certainly the greatest player that Ireland has ever produced. A contrast in styles; creativity and flamboyance versus nous and killer instinct.

We know the numbers - Scotland must win by eight (something they haven't done against Ireland in a competitive match for 22 years) and deny Ireland a bonus point to boot. It's a riveting prospect and it became all the more compelling when Russell started speaking about it the other day.

"I wouldn't say we need to go over the top and put him off his stride - or take him out," he said of his counterpart. "We just need to be aware of what he can do and how he can control the game. If we go all-out to shut him down then that creates space elsewhere, which is probably what they want.

"I'll play my own game. There will always be a battle against the man in front of you, but I don't intend to get caught up in that. There might be some mouthing off here and there. I wouldn't expect anything else. Not from me, never from me."

The fly-half smiled at the notion. "Anything you can do to get one up on the other team," he suggested. "If we get momentum, it might be somebody like Peter O'Mahony trying to start some handbags or maybe one of us trying something. It's inevitable that something is going to happen."

Russell says he'll be telling his team not to think about the outcome too much, not to get bogged down in the pursuit of an eight-point win when Scotland have not produced any kind of win against Ireland in eight Tests.

"We've definitely got nothing to lose," he said. "I think there'll be a bit of running rugby this weekend."

That's his dream, of course. A fractured game, a chaotic mess. "I wouldn't say there's more pressure," he suggested. "It's easy to say it's just another week, but it's not because it's knockout rugby.

"Ireland have been in more big games than us and have won more big games than us, but the important thing is to enjoy it. It's not often you go into a knockout game at the World Cup against the number one team in the world with all your family and friends there."

Russell says he doesn't get nervous before games, but he knows the enormity of what's coming, knows that there is more on the line on Saturday than there has been for an awfully long time. Is this the biggest game of his life?

He talks about the dramatic, and controversial, quarter-final against Australia at Twickenham in 2015 but then says that, because this one is staring him in the face, then nothing in his career has been bigger than this do-or-die pool game with the team who have almost forgotten what it feels like to lose.

"It's going to be a massive occasion and it's a chance to show how good we can be," Russell said. "Having a bit of swagger is a good thing. Hopefully we see that [from Scotland] on Saturday and that it's not the other way around."

There was a fascinating admission that he, and his team, got certain things wrong in the pool opener against the Springboks. "I've learned a lot from that game," he said. "I think we chased it a little bit too early. If Ireland do get ahead, we don't need to score straight away. We need to stick to our structures and our strategy.

"It's something we touched on after South Africa. We felt that we didn't have many chances, but when we looked back at the game, there actually were a few chances. I don't know if it was the pressure of the first game of the tournament, or the pressure their defence put us under, but we never really saw the chances.

"A key message was to keep backing ourselves. Even if we are under pressure, keep pulling the trigger and going for it. If we are going to beat the number one team in the world, we have to make sure we take our chances."

Did they over-think it against the Boks? "Potentially. I thought a lot about their blitz defence and I was almost looking more at their defence than what we could do in attack. So this week will be more focusing on us and what we can do to put Ireland under pressure. It'll be about going after them and trying to take them on."

That's the only way Scotland know how. It's their best, and only, chance. In Darcy Graham and Duhan van der Merwe, they have lethal wings, given the opportunity. Graham has scored 12 tries in his past seven Tests and 24 in 38 overall. Van Der Merwe has seven in his past 10 and 21 in 33 caps. Those numbers are pretty special.

Ireland will have a plan for them, of course. When Russell says "the quicker we can get the ball into Darcy's and Duhan's hands, the better" then one of the great defences in the global game will have something to say about it, as did South Africa, who ruthlessly shut down Scotland's attacking function.

"Inside of the wings, Blair [Kinghorn] has been outstanding, Sione [Tuipulotu] and Shuggie [Huw Jones] are working so well together," Russell suggested. "We've got so many threats throughout the back-line.

"The finishing ability of these boys is outstanding. Duhan scored one against England from nothing. Darcy's scored in the last two games from nothing. He's three tries away from Hoggy [Stuart Hogg's record of 27 Test tries] and Duhan's six away. It's inevitable they pass Hoggy."

In a game that Scotland need to win by eight, there was mention the other day of scoreboard pressure and the possibility of Russell orchestrating a drop-goal policy where possible, just to keep the points tally ticking over.

It was news to him. In his 74 caps, Russell has scored eight tries, landed 43 penalties and 77 conversions for a points total of 323, but the one thing he hasn't done is drop a goal. For a fly-half, nine years into his Test career, that's astonishing.

In 2016, he missed a drop-goal against France and England, then missed two against Argentina the same year and had one charged down by Dan Biggar in 2022.

"I've attempted a few drop-goals in games in the past, but I don't think I've ever hit one," he admitted. "Hopefully it doesn't come down to that. I haven't actually thought about it. I'll get a few tips off Ben [Healy]. He's the man for drop-goals."

The tale of the tape for Scotland versus Ireland shows that they've created excellent opportunities in most of the losses they've suffered, but their wastefulness, coupled with Ireland's ruthlessness, has done for them. That can't happen again, Russell said.

"It'll be tough to beat Ireland. They don't concede any soft tries and they're very disciplined. To beat them by eight points, that'll potentially be down to our defence to hold them out while also taking our chances. There probably won't be many. When we do get them, we need to take them."