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."
Beating Merthyr has boosted Carmarthen Quins hopes of reaching a top eight spot in the Principality Premiership. Quins captain Haydn Pugh is delighted with his team's progress and is determined that everyone from the Under 6s through to the senior team, enjoys the ride.
When the Wales squad were asked to nominate individuals who played a big part in their early playing days, Wales and Dragons full back and wing Hallam Amos thought of his former Monmouth School rugby coach John Bevan.
Sam Cross and Luke Treharne have been named as co-captains of the Wales Sevens side as head coach Gareth Williams names his 12-man squad to play in the first leg of the HSBC World Series in Dubai next weekend.
Bedwas head coach Steve Law and players Nicky Griffiths and Alun Rees extol the virtues of the close knit club as they prepare to host third place RGC 1404 - who are one place head of them on the Principality Premiership points table - on Saturday.
Many of the Wales squad have said Diolch (thank you) to someone who played an important part in their early playing days by nominating them to be invited to the Wales v South Africa match. One person, Gowerton Comprehensive geography teacher Mr Dean Mason was nominated by two of his former pupils, Dan Biggar and Sam Davies.
The second WRU disability rugby pilot has been delivered, this time in Caerphilly schools, culminating in a festival at the Caerphilly Centre of Sporting Excellence, Ystrad Mynach tomorrow. Plans are in place to set up a Disability Rugby Club in Newbridge to provide long-term playing opportunities.
WRU TV: Hear from inside the Wales camp as Neil Jenkins discusses this weekend's clash with South Africa and how the squad are looking to put in a strong performance to round of the 2016 Under Armour Series