England prop Mako Vunipola will be gripped by anticipation as Saturday's decisive RBS 6 Nations clash with France nears its climax, knowing he could have a critical late role to play.
Wales and Ireland are also competing for the title on an afternoon of staggered kick-offs that promises a nerve-shredding conclusion to a Championship that will almost certainly be decided by points difference.
Favourites England are in the driving seat as they will be aware of the target they require if they are to lift a first piece of silverware under head coach Stuart Lancaster, raising the prospect of a pivotal final quarter at Twickenham.
It is in the midst of this scenario that explosive front row Vunipola will be summoned from the bench and ordered to wreak as much havoc as possible for the brief time he is on the pitch.
"The last 15 minutes against France could be the most crucial spell of our Six Nations so far, so we know we have to come on and make a difference," Vunipola said.
"As a bench we're always trying to have an impact on the game. When you're coming on in the last 10-15 minutes, there can't be any excuses like you're tired.
"Every replacement player gets restless in that second half. We all want to get on as soon as possible and get ourselves into the game.
"Around the 60-minute mark you're on the edge of your seat waiting for the coach to give you the heads-up, but you have to try and stay relaxed and composed until you get the call.
"When you go on, the first thing to do is ensure the set-piece is stable and then try to get involved as much as possible, get your hands on the ball, make tackles, get around the pitch and make an impact.
"The bench has a massive role to play in the game now. It's not just about the XV, it's about the 23-man squad.
"France have world-class players on their bench who come on and make a massive difference for them. We have to make sure we do the same."
Vunipola will operate in the eye of the storm as the giant English and French packs slug it out over 80 minutes in search of the foothold that will propel their team to victory.
Lock Courtney Lawes has described Les Bleus' forwards as "big dudes" and Vunipola insists the Red Rose must be ready to fight fire with fire as they seek to end a sequence of three successive runners-up finishes in the Six Nations.
"We've seen the threat France pose with their pack and they have some big, heavy boys with an all-round game, but their set-piece is their bread and butter," Vunipola said.
"As a pack we have to stand up to them first and foremost and then challenge them with our all-court game.
"I think they're the biggest pack we play against. Uini Atonio (tighthead prop, 6'4" and 25 stones) is a big boy and you don't want him running at you at full pace.
"They have some big boys, but we have some big boys ourselves so we have to stand up to them and match them in terms of physicality.
"These big forwards nowadays are massive but they can still get around the pitch."
England start as pre-match favourites and are 4/5 to win the Championship, but Vunipola insists they must be pitch perfect if he is to celebrate winning the title alongside brother and team-mate Billy.
"Winning the Six Nations has been our target and to do it would be massive. We lost to Ireland but now have another chance to do it. We will have to perform at our best to beat France," Vunipola said.
"Just to win the Six Nations is special. The added bonus would be that my brother will be there. It's added motivation for us to go out there and perform."