Liam Williams will win his 50th Wales cap against Tonga on Sunday (AEDT) while Dan Biggar will play at fly-half in a team featuring 14 changes.
Billy Vunipola capped an outstanding display by scoring the decisive try in Saracens' 25-20 derby win over Harlequins in the Premiership.
Last season's Premiership finalist Saracens and Exeter Chiefs maintained their unbeaten starts to the new campaign with wins in the Premiership.
Dan Biggar struck a post with the last kick of the game as Bath edged out Northampton Saints, while Bristol Bears extended Harlequins' Premiership losing streak and Wasps saw off Sale Sharks.
Exeter Chiefs and Saracens maintained their unbeaten starts to the new Premiership season to make it three wins from three.
Bath was denied victory over local rival Gloucester by a familiar face, while Billy Vunipola marked his return to action with a try for Saracens on a busy day in the Premiership.
Sergio Aguero struck twice, while Vincent Kompany, Fernandinho and Gabriel Jesus were also on target as Manchester City thumped Watford 5-0.