Japan's Blue Samurai have defied expectations at this year's World Cup, but coach Akira Nishino admits there's one thing the team hasn't practised: penalties.

That's despite both Russia and Croatia relying on heart stopping spot-kicks to secure their places in the quarterfinals on Sunday.

"We've never practised penalty kicks as a team," Nishino told reporters on Sunday in Russia, the Sankei Shimbun daily said.

"I don't think it is really useful to practise for a penalty shootout," he added, saying it was impossible to recreate the pressure players would feel in a real penalty situation.

"Individual players who wanted to be ready trained on their own, but not as a team."

After a poor run-up to the tournament, few people expected Japan to get very far, with most predicting they would not make it out of their group.

But despite the team's success, Nishino has endured stinging criticism for instructing players to run down the clock and settle for a 1-0 defeat against Poland, knowing it was enough to advance.

They squeezed into the knockout rounds at Senegal's expense because they had picked up fewer yellow cards.

Nishino stepped in as coach just months before the World Cup, after Japan's Football Association unceremoniously canned his predecessor Vahid Halilhodzic.

The Franco-Bosnian is suing over the decision, and denies claims that communication between him and the team had broken down.