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."
WRU International Skills Coach Jason Strange is a busy man, combining the new role with that of Wales Under 20 attack coach, Ebbw Vale head coach and continuing to teach at Ebbw Fawr Learning Community.
Warren Gatland and Sam Warburton look ahead to this week's crunch RBS 6 Nations tie against France, where the Wales skipper in particular is keen to make his mark, as Paris has proved a bleak place for him in the past.
Following their historic win over England, Wales Under 20 suffered a narrow, 36-34 loss to their Scottish counterparts last weekend, despite outscoring them by five tries to three. Watch the match highlights and reaction.
WRU TV go behind the scenes with the Wales squad as they put the final touches in place ahead of the clash against Scotland at Murrayfield. Follow the squad on their captain's run, the kickers visit to Murrayfield and Neil Jenkins' press conference