Justin Tipuric says "it is time to perform" when Wales face a World Cup showdown against Australia that could shape their destiny in the tournament.
Victory for Wales against the Wallabies would install them as red-hot favourites to win Pool D and secure a likely quarter-final appointment with France or Argentina.
But if Australia beat Wales for a 14th time in the last 15 meetings, it could send Tipuric and company hurtling towards a last-eight clash against England.
"There is no bones about it, both teams want to try and get through and finish top of the group," Wales flanker Tipuric said.
"There have been some tough results in the past, but it was nice to get a win last autumn against them (Australia).
"I think they will be chomping at the bit to get that back from us, and we want to make sure we get another win.
"Before we even came in here, you knew this was going to be a big one. Now we are here, it's time to perform, really."
Wales have only claimed one victory against Australia, New Zealand or South Africa in World Cup history - and that was 32 years ago in a third-place play-off when they toppled the Wallabies.
And their overall record under head coach Warren Gatland shows just seven wins from 41 attempts at the hands of the three southern hemisphere heavyweights.
Wales halted a 13-Test losing sequence at Australia's hands last November, with Tipuric set to be among several survivors from that 9-6 success who run out at Tokyo Stadium on Sunday.
Asked if there had been a mental block prior to that win, Tipuric added: "It's tough to say.
"Those games are so tight, there is maybe... people would expect there was a bit of a mental block, I don't know.
"In the end in the last game we probably left about 15 points out there, so it made the scoreline look a lot closer than it actually was."
If Wales are to triumph, then Tipuric's battle at the breakdown with Australia's revered back-row double act Michael Hooper and David Pocock will be crucial.
The 67 times-capped Tipuric has encountered both players on several previous occasions, and he knows exactly what is coming.
"They are absolutely world-class sevens," he said. "When you play against world-class back-rowers you always know you are going to be in for a tough game.
"Those two are consistently up there with the best in the world. You know what type of game you are going to be in for.
"Pocock is one of the best players in the world over the ball defensively - and Michael is more of an attacking seven and probably has a bit more of a rugby brain to be in the right place at the right time.
"You would rather play the best players in the world and challenge yourself, rather than face a back-row that isn't as good. You want to play against the best, and you know against those two you will have to be on form.
"I wouldn't say that Sunday is so much a cup final, but it's an important game for us in this World Cup.
"Momentum is an important part of it. If you keep on building and putting in good performances, you are going to be flying and tough to beat."