Best: We need to use edge on tired Scottish
Captain says ‘Fatigue factor’ works for Irish
The F-Word could well become a defining factor as Ireland and Scotland bid to finish the Six Nations on a high.
It will be a true achievement for Scotland because the last time they racked up three wins in the Six Nations was 20 years ago when it was still the Five Nations.
This would be a first for them.
For Ireland, it is all relative to the final days of the previous two seasons. This is more about avoiding a low than achieving a high.
Captain Rory Best was adamant that the 'Fatigue Factor' from Scotland's six-day turnaround will only come into the equation if Ireland can make it relevant.
"I think we need to be accurate with the ball," said Best.
"We need to keep the ball and make Scotland make tackles, regardless of the six or seven-day turnaround.
"That's how we control the tempo. That's how we control the game by keeping hold of the ball. That's when we look at our best."
The hometown advantage and the extra day of recovery can be brought to bare in the final quarter if Ireland can sap the energy out of Scotland.
"It can be a factor if you put pressure on teams and you make them go backwards all the time. All all of a sudden, you start to feel tired.
"If you're on the front-foot, breaking tackles and the opposition are handing the ball back to you easily, fatigue doesn't become an issue because you're relishing being out there."
The lead-in has been complicated by the indication from coach Joe Schmidt that he will make a decision on whether or not to extend his contract to the 2019 World Cup in Japan.
"From a player's point of view, you want to know what's happening," said Best.
"I don't think there are too many players in this squad at the minute that are planning the next World Cup, certainly I'm not.
"If you start to look too far ahead you start to lose focus on what's important and what's important is Saturday.
"It's probably more important for the IRFU and the coaching structure themselves that they get that right.
"From our point of view, no matter what Joe does, we will enjoy and love playing under him until such time as he goes.
"Then, after that, it will be whatever coach comes next, you'll adapt and you'll take the positives and negatives from that and move on."
Ireland have to break Scotland's will to keep going by either starting fast and keeping the foot down or by gradually wearing them out.
That is no easy assignment against a nation reborn. Ireland scrum coach Greg Feek worked with Vern Cotter at Canterbury Crusaders as well as spending the last six years with Schmidt.
"I think having had him and then Joe, you can see a correlation between the two," said Feek.
"He's got some really good smart things around the physical side of the game that he likes to do."
To take people with you, you have to have complete buy-in from top-to-bottom of the organisation.
"He is quite good at making people feel a part of something which Joe also is.
"As a player, when you have an environment where you feel connected to it that's the key to establishing everything else to go forward Vern and Joe both have that as a strength."
The employment of former Leinster and Clermont-Auvergne second row Nathan Hines, also a veteran Scotland international, as a 'resource coach' reflects a like-minded approach with Cotter when it comes to what needs to be done in the trenches.
"The biggest thing Hinesy brought was he walked the talk," said Feek.
"He wasn't a big ranter and raver. But when he did say something the boys listened. He did the job on the paddock. He was physical.
"He had a few little tricks here and there that sometimes worked for us as well that he learned through experience, maybe holding someone into the ruck a little longer or blocking someone out of the way without being too obvious and just being cute at the lineout.
"He obviously had massive international experience. He is not there by accident."
Ireland have to match uncompromising Scotland at the set-piece where having the ball will be a priceless possession.