Tokyo - Pumas coach Mario Ledesma and former France star Fabien Galthie, now in the Les Bleus coaching set-up, have a feisty personal history that will add extra spice to Saturday's France-Argentina clash at the Rugby World Cup.
Ledesma spent 13 years plying his trade in France, first as a player then a coach, until his stay came to an abrupt end in 2014 after a row with Galthie, then his boss at Montpellier.
After a brief coaching stint in Paris with Stade Francais, Ledesma arrived at the southern French club in 2012 to take up a position as Galthie's deputy -- but relations between the pair quickly turned sour.
A very different management style and an awkward power struggle between the boss and the deputy created a powder keg atmosphere at the club, explained Thibaut Privat, a former international lock close to Ledesma.
"Fabien's management style did not chime with Mario's philosophy. When we got into difficulty in the autumn in 2014, there were a couple of problems. That's when the disagreements between them started to be voiced more loudly," Privat told AFP.
It came to a head on November 7, 2014 after a shock 25-10 home defeat to Brive.
Behind closed dressing room doors, some uncomfortable home truths were told. Arguments broke out between players and coaches amid mounting tension between Galthie and Ledesma.
The row culminated in a physical confrontation between Ledesma and hooker Charles Geli.
Things had to change and billionaire Montpellier president Mohed Altrad decided it was Ledesma that had to take the fall. Galthie, meanwhile, distanced himself from his former deputy.
"I can understand that Mario took it badly that Fabien failed to stick by him," said Privat, who was playing for Montpellier at the time.
"It is a surprise to see the deputy kicked out instead of the head coach. Often, it is the latter that is sacrificed," said Privat.
In the event, Galthie himself left the crisis-hit Montpellier at the end of the year.
As for Ledesma, he went on to join current Wallabies coach Michael Cheika, first at the Waratahs, then the national side. He returned to his native Argentina in 2018 to coach the Pumas and Super Rugby club the Jaguares.
His in-depth inside knowledge of France and French rugby is seen as a plus ahead of the crunch Pool C clash which could see the losers struggling to get out of the 'group of death' that also includes England.
Los Pumas fly-half Nicolas Sanchez told AFP in an interview: "He has played many games against them and he knows how they prepare, what they have in their heads before this type of game."
"He's worked with Galthie. All these things count," added Sanchez.
Ledesma told reporters at a pre-match press conference: "I don't know if we will bump into each other or not."
"I think we will both be in the stands. But I don't know if we will see each other before or after the match."
The post-match handshake will be one to watch.