Dan Biggar to start for Wales in World Cup quarter-final against Argentina

Biggar sustained a chest injury in the 40-6 thrashing of Australia but was forced into action as a replacement against Georgia after Gareth Anscombe, initially down to start, had to withdraw with a groin injury.

Flanker Jac Morgan is back to captain the side after being rested for the 43-19 win over Georgia that saw Wales finish unbeaten in their pool after previous victories over Fiji, Portugal and Australia.

Gatland made six changes to the team that defeated Georgia, with three in the forward pack and three in the back-line.

"We had a goal of making the quarter-finals which we have achieved. Now it's about building on that momentum," said Gatland, who is eyeing a third World Cup semi-final appearance with Wales.

"It's exciting to enter into the knock-out stages of the tournament and we are ready for the challenge of a quarter-final. All our preparation has been geared to getting to this spot and we're very much relishing the opportunity.

"We're expecting another tough encounter this weekend against a physical Argentina side. We haven't had the perfect performance yet, but we have shown that we are a hard team to beat."

Gatland added: "There is a lot more growth in this squad – collectively and individually – and we can't wait to get out there in Marseille on Saturday."

Morgan makes his fourth start of the tournament and is joined in the Wales back row by Tommy Reffell (openside flanker) and Aaron Wainwright, at No. 8 in place of Taulupe Faletau, who broke his arm against Georgia.

Ryan Elias is named at hooker alongside props Gareth Thomas (loose-head) and Tomas Francis (tight-head), while Adam Beard partners Will Rowlands in the second row.

Biggar is joined by Gareth Davies in the halfbacks, as Nick Tompkins and George North continue in midfield, the latter making his 20th World Cup appearance in his fourth tournament.

Liam Williams has overcome a bang on the knee to be named at full-back with Josh Adams and Louis Rees-Zammit on the wings.

Hooker Dewi Lake and props Corey Domachowski and Dillon Lewis, along with Dafydd Jenkins and Christ Tshiunza, provide forward coverage from the bench.

The back line cover comes in the form of Tomos Williams, Sam Costelow and Rio Dyer.

Wales (15-1)

Liam Williams; Louis Rees-Zammit, George North, Nick Tompkins, Josh Adams; Dan Biggar, Gareth Davies; Aaron Wainwright, Tommy Reffell, Jac Morgan (capt); Adam Beard, Will Rowlands; Tomas Francis, Ryan Elias, Gareth Thomas

Replacements: Dewi Lake, Corey Domachowski, Dillon Lewis, Dafydd Jenkins, Christ Tshiunza, Tomos Williams, Sam Costelow, Rio Dyer