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From the coliseum to the cauldron, via Landsdowne Road, Ireland arrive in Cardiff a different team to the one that left Rome, victorious on paper only.
But what happened in Dublin 4 last Sunday informs much of the narrative around today's game, which is set to be played out in the rain after Ireland requested that the roof remain open against the hosts' wishes.
A failure to fly against France would have made this task an awful lot harder. As it is, Ireland released the pressure valve against a gormless Les Bleus outfit and are in bonus territory, not that they will admit it.
"We feel that we posted a performance last week that was a lot more reflective of us and the way we are and how we go about playing matches," captain Rory Best told RTÉ Sport, coming as close as he could to saying that the France game was more important than this afternoon's meeting.
A particularly popular line this week is that defeat to the Grand Slam chasers wouldn't be the end of the world, as long as Ireland make it a contest.
It rings true; the "blip" of England, Scotland and Italy is in the past, said Jack Conan last week. "We're back."
"If it's a very good display, a very good game and it's a one-score game either way, I think that gets us a lot closer to where we want to be," said former Ireland boss Eddie O'Sullivan on Against the Head.
Games between Joe Schmidt's Ireland and Warren Gatland's Wales have always been close, hard-fought by nature and today's match threatens to be the same.
A win will bring Gatland a third Grand Slam before he finishes his stint in charge after the World Cup.
Victory for Ireland would more than likely see them leapfrog the table-toppers (although a freakish scoreline whereby Wales claimed two bonus points in defeat and the visitors just four match-points would mean Gatland's side could still finish higher). Don't worry too much about that.
That equation is of little concern to Wales, who are only Grand Slam-minded and will have factored in England putting Scotland to the sword and finishing on 20 points.
Ireland's record in the Principality Stadium is not impressive with Schmidt yet to taste victory in the Six Nations, losing in 2015 and 2017.
They may have scored five tries in Dublin last year but have only a penalty try to brag about from those two defeats.
With Wales' defence the pillar of their campaign – they average one try conceded every 53.3 minutes compared to Ireland's 35.6 minutes – five-pointers may be in short supply.
That means Ireland must play smart: whereas last Sunday they refused to take three-pointers when they were presented with certain three-pointers, Best, making his last Six Nations appearance, may be working under different instructions.
While it might be hard to find a team more defensively disorganised than France, Wales have been outstanding in that aspect, conceding just six tries this season.
Their hold-out towards the end of last week's 18-11 win over Scotland was reminiscent of the opening 10 minutes of the second half of England v Ireland last year – a passage of played picked out by Schmidt as a campaign highlight.
An extra bite and focus in defence is inherent to being within touching distance of Grand Slam glory, it seems.
"These players are on a very good run. They are a hugely impressive group and they deserve to be going into the final weekend with everything to play for," said Gatland.
Wales are also on a 13-game winning streak although that won't bother Ireland who stopped New Zealand and England (in the 2017 Grand Slam game) on 18-game runs.
"I pride myself on the record I have had in big matches when it has really mattered," Gatland added.
As far as personnel go, the hosts have named an unchanged XV, which means that Liam Williams, who left the pitch in Murrayfield with his shoulder in a makeshift sling, starts at full-back – he's surely in line for a player of the championship awards – and adds a cutting edge that may make a difference.
Ireland make three changes: Rob Kearney returns after overcoming the calf strain that saw him miss the France game; Sean O'Brien comes in for the injured Josh van der Flier (groin) and former Scarlets player Tadhg Beirne (above) gets a Six Nations debut in place of Iain Henderson (knee).
"He knows these players pretty well," said Schmidt of the Munster forward.
"Obviously, he's played plenty of times against the second rows that are going to be there with Adam Beard and Alun-Wyn Jones. I think he is as ready as we can get him to be at this stage and I know he's incredibly motivated."
O'Brien, it could be read from Schmidt's comments, needs to produce the goods.
"What’s on the line for this for Ireland?" asked Stephen Ferris on the RTÉ Rugby podcast his week, cutting to the crux of the matter.
"You get a result, you need a crazy result with Scotland beating England.
"So it’s just about putting in a performance, trying to get the victory for Ireland, trying to keep a bit of momentum going towards the World Cup warm-up games whereas for Wales, this is everything.
"They will do anything in their power to make sure they win this match and create more history in a Welsh jersey."
Wales Liam Williams; George North, Jonathan Davies, Hadleigh Parkes, Josh Adams; Gareth Anscombe, Gareth Davies; Rob Evans, Ken Owens, Tomas Francis, Adam Beard, Alun Wyn Jones (capt), Josh Navidi, Justin Tipuric, Ross Moriarty.
Replacements: Elliot Dee; Nicky Smith; Dillon Lewis; Jake Ball; Aaron Wainwright; Aled Davies; Dan Biggar; Owen Watkin.
Ireland: Rob Kearney; Keith Earls, Garry Ringrose, Bundee Aki, Jacob Stockdale; Johnny Sexton, Conor Murray; Cian Healy, Rory Best (capt), Tadhg Furlong; Tadhg Beirne, James Ryan; Peter O'Mahony, Sean O'Brien, CJ Stander.
Replacements: Niall Scannell, Dave Kilcoyne, Andrew Porter, Quinn Roux, Jack Conan, Kieran Marmion, Jack Carty, Jordan Larmour.
Referee: Angus Gardner (Australia)
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