Italy a different team when Sergio Parisse plays
Ireland and Italy both know, deep down, the absence or presence of Sergio Parisse can make, not just a difference, but all the difference.
The problem is the Italian captain had not trained for three weeks from a calf haematoma and time was fast dissolving when he landed in England from his intensive physiotherapy in Paris.
The fact he travelled over and dived straight into training on Tuesday boded well for coach Jacques Brunel.
However, the 32 year-old still had two hoops to jump through at training on Wednesday and a rigorous fitness test yesterday.
The truth of his availability will be revealed today.
Leinster coach Leo Cullen summed him up: "If you hear the word talisman, you would have a picture of someone like him in your head.
"He's been head-and-shoulders Italy's best player for the last 10-12 years."
All the years in the trenches have delivered very little in terms of the glint of silverware until he led Stade Francais to the Top-14 title last season, dominating against all-powerful Toulon in the semi-final and Clermont-Auvergne in the final.
The release of emotion revealed a man who believes a winner really does have to be defined by the medals on his chest.
There have been the French championships of 2007 and 2015, the European Challenge Cups of 2011 and 2013 and the Italian Cup for Treviso in 2005.
"You can see with Stade Francais in the Top-14 last year the influence he has there," said Cullen.
Of course, there has been nothing but the instant hit of one-off victories for Italy over the course of his 113 caps.
In 2013, Parisse drove them to their second-ever defeat of France and concluded an otherwise fruitless campaign with their first win over Ireland.
"Italy are a team capable of rising to the occasion," warned Cullen.
"They know this is their last chance. They haven't performed great in the lead up to this game.
"Anyone's capable of producing the goods on the day. That's what Ireland has to guard against."