Mark Jones has told his Wales youngsters they need to improve if they are going to make more of an impact at the World Rugby U20 Championships in South Africa.

The young Dragons had to come from behind to beat Japan, 41-19, in Stellenbosch but it was far more edgy than the scoreline suggests.

Until Japan captain Yoshiki Omachi was sent off early in the second half for a dangerous tackle, the underdogs actually led 19-15.

Wales, though, were unable to make their player advantage pay until the 65th minute when replacement Tom Florence went over in the right corner following a dominant attacking scrum.

The result remained in the balance until the final six minutes when Dan Edwards, Bryn Bradley and Louie Hennessey each crossed the whitewash to put some gloss on the victory.

Wales coach Mark Jones admitted: “Japan really fronted up, especially at the set-piece where they probably edged us out for large parts.

“We always knew it was going to take an 80-minute performance and the dam may burst eventually under constant pressure. I just wish it had burst a little earlier.

“We got what we wanted from this game in terms of points but our discipline was poor and we know we’ve got to go up another three or four gears when we face France.”

France is likely to be Wales’ toughest game of the pool stages as they showed they mean business in defending their title with a convincing 35-14 win over New Zealand in torrential rain in Paarl.

As the Wales U20s get ready to face France, the seniors are preparing for their visit to France in September for the World Cup.

Much has been written about the tough training sessions Warren Gatland’s squad have undergone, but Wales and Scarlets scrum-half Gareth Davies has revealed other skills have been honed, too.

In a change to routine training sessions, the squad spent a day at ‘The Green Mile’ – a health and wellness centre where the players were also subjected to other, psychological challenges.

“It was a good day,” Davies said of the different approach as he explained the activities undertaken.

“We had a mental challenge where they put us in some stressful positions. We weren’t allowed to talk for an hour. They put a bag over our head so we couldn’t see where we were and they moved us around the camp.

“There were some weird stressful noises in the background. It was good, quite challenging. We knew it was going to be around the hour mark but it felt like we were there for three or four hours.

“But we felt really good after it. We bonded well as a team and got some good positives from it.”