OITA, 16 Oct - Liam Williams is reluctant to admit that he is in danger of becoming an over-achiever.

The last 12 months for the Swansea-born full-back have been like a dream. He won the Six Nations Grand Slam with Wales, then went on to take the Premiership title in England with Saracens before helping them to be crowned European champions.

It has led the ex-scaffolder to ponder that completing a unique quadruple by adding the world title next month might leave him with little else to aim for.

"If I win this one I’m done," he said on Tuesday, before immediately adding. "That’s just a joke."

For the time being, Williams, 28, is content to focus on a World Cup triumph to give coach Warren Gatland a dream send-off.

The next rung on that ladder is Sunday's quarter-final against France at Oita Stadium.

"There's only one thing we think we can do and that is win it," said Williams, who helped Wales top Pool D with a perfect record.

"I wouldn't say we've got the easy route to the World Cup but we've got France next and we need to beat them to be looking at the bigger picture. I think we can go on and win it."

Williams said the Welsh squad were pleased after winning four out of four matches in Japan, but stressed that such form would mean nothing if they were sent home by Les Bleus this weekend.

"We have beaten France seven times out of the last eight but this is the biggest one," he said. "They have been playing well in this World Cup so it is going to be a tough one.

"But over the past 18 months we've won the Six Nations and we've been away on a couple of these training camps and it has all brought us in to one huge team.

"Gats (coach Warren Gatland) gives us a lot of energy, so we'll take that out on to the training pitch. We’ll have a laugh and a joke but when it comes down to working we'll work."

Wales's potential path to the semi-final could see them face Japan – the only other team to win all their pool games – should the hosts continue their heroics against South Africa.

And Williams admits he is loving the Brave Blossoms' attacking, open style of play.

"They were unbelievable, fair play to them," he said. "We know it has been quite hot out here and sweaty, so the passing was unbelievable and they played with some real structure as well, which was just amazing. Scotland didn't really have any answers.

"Japan like to keep the ball in hand. It depends what works for a team. But we were watching it in the changing rooms after our game against Uruguay and it was unbelievable.”

Wales have been boosted with fly-half Dan Biggar back in training, having come through return-to-play protocols after his collision with Williams against Fiji left him flat on his back.

The duo had also clashed heads in the warm-up before the opening game against Georgia.

"The ball was in the middle of the two of us and he is not one to back out so I went up for it and unfortunately caught him in the air - and on the way down.

"He said after the World Cup it is his turn to knock me out."

RNS ig/sg/ar/djk/sw