Fly-half Dan Biggar says Wales know their path to World Cup glory could rest on Sunday’s crunch Pool D game against Australia.
An easier route in the knock-out stage is likely to rest on the outcome in Tokyo.
England are favourites to win Pool C ahead of France or Argentina with Wales in line to face one of those sides.
“The bottom line is we’re fully aware what topping our group means,” said Biggar.
“We are getting into the real depth of the tournament and Sunday’s result will have a big impact on the pool.”
England have started with wins over United States and Tonga, but are yet to play France and Argentina in their group.
Coach Eddie Jones will be in the Tokyo Stadium crowd scouting England’s potential quarter-final opponents.
“I don’t think England will have it all their own way, they have the two toughest fixtures to finish, but they are looking strong, aren’t they? ” said Biggar.
“Gats [Warren Gatland] said in a meeting on Friday we’ll probably be playing France or England in the quarter-finals, so it’s one of those where France on their day are as good as anyone in world rugby.
“For us we’re not focusing on that, we are looking to get the job done on Sunday which would put us in a strong position to get out of the group.
“You get the sense that the winner on Sunday puts themselves in one heck of a strong position and the loser probably has a bit more pressure on them the week after.”
‘Bit more belief’
Australia have won 13 out of the past 14 games against Wales.
Gatland’s side finally defeated the Wallabies 9-6 last November with Biggar kicking the winning penalty.
Australia have identified Biggar as a key Wales figure and have also reshuffled their backline selection to counter his kicking game and aerial ability.
Experienced half-backs Will Genia and Bernard Foley return, and Dane Haylett-Petty comes in at full-back, while Kurtley Beale drops to the bench following signs of vulnerability under the high ball.
“The relief to get the win against them in November was big and it gives us a little bit more belief and confidence going into Sunday’s game,” said Biggar.
“The players they have picked are still excellent players. They’re probably bringing a little bit more stability to their team.”
Captain Alun Wyn Jones will break Wales’ cap record with his 130th appearance for his country and has said blood has been spilled in training.
Biggar has not been short of friendly fire from his team-mates having been struck on the chin by James Davies in the warm-up against Georgia before also colliding with Liam Williams during the game.
The 29-year-old has reported a clean bill of health and says Sunday’s showdown is the sort of match players dream of being involved in.
“It is one of those where if you are not excited about playing in big games in World Cups like this then you are in the wrong sport,” said Biggar.
“This is what everyone has worked all summer for.
“This is why we have given up all our weeks for our families, being away for three months in the summer.”
Australia clash vital for Wales}