Head coach Steve Tandy warned Wales must improve after a hard-fought 28-21 Nations Championship victory over Japan in Cardiff.

Wales recorded a bonus-point win as Josh Adams (2), Archie Griffin and Louis Rees-Zammit crossed, but they had to produce a desperate rearguard in the final moments to prevent Japan from an equalising score and a famous draw.

“It’s obviously good to start the campaign with a result, but I can’t run away from the performance when I talk about it,” Tandy said after only the fourth win of his 13-match reign.

Wales head coach Steve Tandy said his side must improve after their victory over Japan (Mike Egerton/PA) (PA Archive)

“There are elements of the performance we definitely need to improve. I thought we’d be better than that in some elements.

“There was really good stuff from us, in terms of the line breaks and how we opened Japan up.…