Shaun Edwards has told Wales' players that Sunday's World Cup clash against Australia is a game they will remember for the rest of their lives.
The Six Nations champions' World Cup destiny could be shaped by what happens at Tokyo Stadium.
The winners will be overwhelming favourites to finish top of Pool D and potentially open up a more straightforward route in the knockout phase.
England and New Zealand, though, are set to loom large for the losers, which underlines huge stakes in what could be the game of the tournament so far.
"Let's be honest, we have been preparing for this since the draw was made," Wales' defence coach Edwards said.
"It's a pivotal game. I said to the players this is a game they will remember for the rest of their lives, and we want to be successful in it.
"Each game is a different entity. Let's get it on. These are two top teams and equally matched having it out in the pool games. Hopefully it will be a good advert for the game of rugby."
Wales beat Australia 9-6 when the countries last met 10 months ago, and Wallabies boss Michael Cheika has installed them as favourites on Sunday.
But Edwards added: "I don't think it matters one jot by the time kick-off comes around. It's all down to the players in the end. All the talk, it doesn't matter one jot.
"I think there will be more points than 9-6, but history tells you there have been a lot of one-score games between us and Australia.
"That's why our discipline is so important. It wouldn't surprise me if it's another one-score game, and hopefully it goes to Wales."
Wales have undergone intense preparations for what is one of their biggest matches since head coach Warren Gatland was appointed almost 12 years ago.
"There has been an edge to us all week," Edwards said.
"The difference for us in this game is that we've had four months of preparation, and normally we have four days.
"It (Australia's attack) has probably changed a little bit in the last couple of years.
"I think their last performance showed that their driven line-out is a huge presence for them at the moment. It definitely got them out of trouble against Fiji.
"The nine and ten are always an emphasis for any team, but particularly for Australia with the experience and the skill they have there.
"As regards to saying we're going to win the World Cup, that has never really been our approach. Our approach has been to win the next game.
"The next game for us is Australia and we are going into it pretty well-prepared against a formidable opponent. Let's get it on."