Ireland might start this Rugby World Cup as the No.1 side in the world, but their Guinness Six Nations rivals Scotland will arrive in Yokohama confident of victory.
Joe Schmidt has often had the best of Scotland during his Ireland tenure, his side have won six of the seven clashes against their Celtic cousins.
But on the big stage, and in what should be a compelling Pool A push for the last eight alongside hosts Japan, anything could happen.
Townsend’s side have shown this past World Cup cycle that they can shred any defence on their day – and they finished their warm-up campaign with three wins on the spin.
Ireland meanwhile succumbed to a second heavy loss of the calendar year to England, but then seemingly put things right with back-to-back wins over Wales.
But this weekend Schmidt has injury concerns in his back line with Rob Kearney, Robbie Henshaw and Keith Earls all missing.
Jordan Larmour, Garry Ringrose and Andrew Conway are decent replacements no doubt, but Scotland by contrast are tooled up and ready for action.
Finn Russell will pull the strings from No.10 while Duncan Taylor at outside centre is back fit and – Scotland hope – firing.
The experienced back three of Stuart Hogg, Tommy Seymour and Sean Maitland will take some stopping if they can get good ball.
But undoubtedly the big battle comes up front, Ireland’s pack is jammed full of British & Irish Lions as well as young tyros like James Ryan and Josh van der Flier.
Scotland skipper Stuart McInally therefore will need to inspire his pack to match power with power and then we could be in for a Sunday show to remember.
Ireland v Scotland, Sunday September 22, Yokohama, 08:45AM (BST)
Joe Schmidt: “One thing I will be really confident of is that we will be tough to beat.
“I don’t think there’s a huge amount between the two teams. It’s maybe whoever does get that bounce of the ball and can be just a little bit more efficient than the other. That may just tip the balance.”
Andy Farrell: “There’s certainly a feel of something brewing of major importance. The intensity, the bite in training, is very significant. I suppose that’s a culmination of what’s happened over the last couple of months.
“Scotland like to take risks, calculated risks. We need to expect the unexpected, try to get ahead of the game.
“We know they like to play with a high tempo, and we need to try to create opportunities from their defence to combat them.”
Scotland head coach Gregor Townsend: “In Ireland we face a quality opposition who, over the past number of years, have earned the right to be the number one ranked side in the world.
“We know them well and are well aware of the strengths they possess throughout their squad.
“We expect them to play very well, as they did in their most recent games against Wales, so only our best performance will do in order to win.
“The prospect of facing them in the opening round of a Rugby World Cup is a fantastic challenge for our players and supporters around the world.”
The two skippers go head to head in the front row on Sunday.
McInally has become such a key component of the Scotland pack, their set-piece game is so much stronger with him in the side.
He is the coming man while Best is the old timer holding on for one last shot at history.
The Irishman’s darts were wayward in the warm-ups but with the world watching, his experience could be absolutely vital.
But keep an eye out too for Garry Ringrose and Duncan Taylor, two men itching to prove themselves in the No.13 jersey and both with an innate understanding of the game to rival the world’s best.
Ireland: 15. Jordan Larmour, 14. Andrew Conway, 13. Garry Ringrose, 12. Bundee Aki, 11. Jacob Stockdale, 10. Jonathan Sexton, 9. Conor Murray, 1. Cian Healy, 2. Rory Best, 3. Tadhg Furlong, 4. Iain Henderson, 5. James Ryan, 6. Peter O’Mahony, 7. Josh van der Flier, 8. CJ Stander
Replacements: 16. Niall Scannell, 17. Dave Kilcoyne, 18. Andrew Porter, 19. Tadhg Beirne, 20. Jack Conan, 21. Luke McGrath, 22. Jack Carty, 23. Chris Farrell
Scotland: 15. Stuart Hogg, 14. Sean Maitland, 13. Duncan Taylor, 12. Sam Johnson, 11. Tommy Seymour, 10. Finn Russell, 9. Greig Laidlaw, 1. Allan Dell, 2. Stuart McInally, 3. WP Nel, 4. Grant Gilchrist, 5. Jonny Gray, 6. John Barclay, 7. Hamish Watson, 8. Ryan Wilson
Replacements: 16. Fraser Brown, 17. Gordon Reid, 18. Simon Berghan, 19. Scott Cummings, 20. Blade Thomson, 21. Ali Price, 22. Chris Harris, 23. Darcy Graham
