The Newport Gwent Dragons scrum-half returns to the Welsh team - winning his 23rd cap - for the first time since the final game of the Six Nations against Italy in March. Cooper came on as a replacement against Romania - scoring a try - and then in last weekend's epic encounter against New Zealand.
But while Japan may be some way below the All Blacks in the world rankings, Cooper insists Wales must focus just as intently. "There's a good feeling in the camp. The boys were pretty happy with the way they performed but obviously gutted that we lost - especially by just one point," said Cooper. "The biggest danger this week is that we become complacent. Last weekend was a great game to watch and be a part of but it has gone.
"We have to focus on a different challenge now because we are in a no-win situation. We are expected to win but we still have to deliver." Cooper won his second and third caps when Wales last met Japan during their tour to the Far East in 2001. Wales won both Tests but are not taking their opponents lightly. "
Japan love to throw the ball around. They were involved in some of the best games of the World Cup but it looks as if they have left some guys back home and brought a new-look team," said Cooper. "But we will not take Japan lightly.
Even though they lost heavily to Scotland, they looked good in the first 20 minutes after scoring an early try. So we will have to play the same way we did against Romania and be clinical straight away."
Whenever Bedlinog tackle Penallta a massive fixure is guaranteed but this Sunday there will be even more emphasis placed on the two rivals when they contest the SSE Swalec Plate final at Principality Stadium.
Ahead of their SSE SWALEC Bowl Final clash with Taffs Well at Principality Stadium on Sunday, Burry Port share their #FABXV nomination with WRUTV in the search for Welsh rugby's greatest volunteers. Everyone can get involved by sending nominations via twitter to @WRU_Community using the hashtag #FABXV
Cardiff Blues prop Gethin Jenkins and Ospreys centre Ben John look ahead to the first game at Principality Stadium in Saturday's double header which is promising to be a special occasion for all Welsh fans.
Carmarthen Quins Director of Rugby Ian Jones and committee member Jeff Thomas along with Llandovery chairman Handel Davies look ahead to Sunday's SSE SWALEC Cup showdown where both teams are out to prove 'West is best'
SWALEC ambassador Shane WIlliams is looking forward to Sunday's Finals Day where the Cup, Bowl and Plate offers a great opportunity for players and teams to experience the magic of playing at Principality Stadium
Carmarthen Quins coach Richard Kelly believes it is an exciting time to be part of the Scarlets region as his side take on local rivals Llandovery in the SSE Swalec Cup final on Sunday, as WRU TV's Graeme Gillespie discovers