Transferring pressure holds key to lasting the pace of daunting task
Keane wants Ireland to make life uncomfortable for French side that will be expected to advance.
There is a chance that a simple Jack Charlton message will always define what a successful Irish football team does best.
"As Jack said years ago, put 'em under pressure," smiled Roy Keane yesterday. "I'm sure there's a song about that you know."
For the challenge of taking on the tournament hosts in a knockout tie, it's a phrase which takes on extra significance.
Irish teams tend to function better when they have the energy and desire to unsettle opponents that are incapable of matching that level of intensity, regardless of whatever skills they might have in their locker.
In Lyon tomorrow, France will be under pressure before they leave the tunnel. Previous Les Bleus generations have shown in the past they are well capable of coping with the burden of expectation on home soil; they are managed by Didier Deschamps, the captain of the 1998 World Cup-winning side.
Still, while the hosts will be well rested heading into the Sunday showdown after a week on the sidelines, Ireland will have to believe they can exploit the anxiety that comes with flying the flag in front of your own.
"Can we take advantage of that somehow? Yeah," said Keane, "That's by getting a foothold in the game.
"Now, a lot of their players are playing for big clubs, I don't think that's something they won't be used to. But you can do that (put on pressure) by tackling, getting the ball into box, with midfield runners, with decision-making, having good energy levels. That all goes into the mix. France look very strong, they look like they are enjoying the tournament and the pressure doesn't look to be getting to them. Hopefully it might now."
The wider football world will be watching. In France, the Thierry Henry handball angle continues to energise the local coverage; a full screening of the controversial 2009 play-off was broadcast last night. Keane became a part of the story at the time by publicly telling upset Irish players to get over it. He had no interest in going there ahead of the flight to Lyon.
"We could be here all day talking about injustices in sport," he shrugged. "I don't think it has any relevance. We have to trust the referee (Italian Niccola Rizzoli) to make the decisions."
The home advantage that troubles Keane is the allocation of tickets. He thought the breakdown would be 60/40. Instead, over 50,000 French followers are expected to be present in the noisy 59,000-seater stadium.
In the must-win match with Italy, the Corkman felt that the green-clad majority in the stands helped to maintain the battery level despite the energy-sapping conditions. The weather forecast indicates that the temperatures will be in the mid 20s around the afternoon kick-off time. Stamina will be a theme.
Both Martin O'Neill and Keane are aggrieved by the quick turnaround. After the drama of Lille, the process of coming back down to earth and then attempting to rise up again for the biggest match of a generation is a major challenge.
There are some parallels with last October when the exhilaration of Germany was followed by a date in Warsaw three days later that could have secured automatic qualification. Ireland laboured, although history would have been rewritten if Richard Keogh had dispatched a late cross by Aiden McGeady.
They have 24 hours longer to recover this time around, and O'Neill must decide whether the lessons of Poland are relevant to his team selection; tinkering with the winning formula has a risk attached.
On that occasion, he responded to a fine James McCarthy display against Germany by bringing Glenn Whelan back from suspension alongside him. The Everton midfielder is comfortable in the chief defensive midfield role, yet there will be a temptation to bring Whelan in for the extra cover.
Crucially, a major injury concern hanging over Stephen Ward means that Robbie Brady may have to be relocated to left-back - that was another change which happened from Germany to Poland when Ward was declared unfit. The alternative options are closer to square pegs in round holes.
Cyrus Christie can do a job at left full without having ever lined out there for Ireland, while Ciaran Clark has some club experience in that sphere. France have deployed Bayern Munich winger Kingsley Coman, the fastest player in the tournament, on the right side in their last two matches. His place is under threat, though. "Where Robbie is playing might depend on how Wardy reacts to his injury," said Keane.
Deschamps has a wealth of options that could provoke sleepless nights. Anthony Martial tormented Seamus Coleman at Premier League level earlier this season, while Dimitri Payet has shone as a playmaker.
The enigmatic Olivier Giroud is tipped to lead the line with French media anticipating that Blaise Matuidi will be retained in the centre of the park. It's unclear what that means for N'Golo Kante and Paul Pogba; the latter was dropped for the slog with Albania before the pack was shuffled for Switzerland with progression assured.
France will have studied Belgium's success and noted that a side capable of breaking at pace can hurt Ireland. However, there is speculation that Deschamps will use Pogba, Kante and Matuidi instead of going with an extra body further forward; that would mean a surprising choice between Payet, Coman, Martial and Antoine Griezmann for just two places.
It's a dazzling array of talent whatever the combination but, as Keane stressed yesterday, Ireland must focus on what harm they can do to France.
"We've got to go with what suits our players," he asserted. "It gives us the best chance of getting a result."
Deschamps' back four has shown signs of weakness with ageing full-backs Bacary Sagna and Patrice Evra guilty of sluggishness and Adil Rami uninspiring next to Laurent Koscielny. James McClean's positivity is a must.
That Keane mentioned runners from deep is significant. Brady's magic moment came from a superbly timed advance. Losing him from that department would be a blow despite his pal Jeff Hendrick offering a strong service in all three matches.
Holding back Wes Hoolahan for the dying stages of the Italian plan worked and Daryl Murphy's inclusion did help to make the ball stick in the opposing half when the direct route was frequently taken.
Jon Walters' return to training opens up the possibility that he could be an option sprung from the bench if the need is pressing entering the final quarter. The bold move if Ward is absent would be to leave Whelan out again and opt for Hoolahan or Quinn as support to McCarthy and Hendrick.
O'Neill might seek to play the long game, however, as edginess could creep into the French ranks if they continue their run of being unable to score in the first half.
Penalty practice has taken place over the past two to three weeks.
"Will that make it easier for the players to score?" asked Keane. "Probably not.
"But it's a nice habit to get into. And if you said to me now we are going to win on penalties ... I'll get back to you on that one," he quipped.
The chance would be a fine thing, but Ireland are tackling an inconsistent force capable of giving teams a chance. O'Neill's men carry the hopes of a nation; France are saddled with the expectation that this is just another step on the road to destiny.
Don't expect an emboldened Ireland to roll over and get out of their way.