Gareth Jenkins was satisfied with his side's performance

Despite the huge scoreline, he said the players wanted to improve further ahead of the final Pool B match against Fiji.

"What we wanted to do was win this game, win it well and play some tidy rugby and I think we've achieved that," said Jenkins.

"But we are not entirely satisfied. There were still aspects of the game that we were disappointed with."

We are challenging ourselves more than anyone else to find the perfect game Gareth Jenkins

Jenkins knows Wales will have to work on turnovers and handling if they are to stand any chance against the Fijians next Saturday in Nantes.

"We are challenging ourselves more than anyone else to find the perfect game," he said.

"There was good stuff there tonight but there was stuff that we were frustrated with as well.

"That's the group we're dealing with. We have got an expectation of improvement."

Jenkins also praised the superb break by Japan which led to Kosuke Endo's try.

"That's what you've got when you play any side in the world.

"If you don't create the accuracy that you need to and you give any team a chance particularly on turnover they will take it and I was applauding that try like everybody else.

"It was a fantastic exhibition of turnover rugby."

Wales captain Stephen Jones also admitted improvements are needed.

"I am happy with the performance, happy with the victory but yes we've got things to work on," he said.

"Some of our patterns weren't as efficient as they should be especially when we go behind we are being turned over.