Japan have swung from high to low at the World Cup but coach Hajime Moriyasu warned his players not to "ride the roller-coaster" of emotions as they prepare to face Spain.

The Blue Samurai can qualify for the knockout round if they beat the Spanish in their final Group E game on Thursday but they will have to pick themselves up after their shock loss to Costa Rica.

That 1-0 defeat on Sunday came just days after Japan had beaten Germany with a stunning comeback, and leaves them needing another upset to advance to the last 16.

Japan could also qualify with a draw against Spain depending on other results but a win would guarantee their progress.

Moriyasu urged his players to keep a level head as he spoke to reporters before training on Monday and insisted the loss to Costa Rica was "already in the past."

"We don't want to get either too up or too down - my approach doesn't change," he said.

"Of course when we win I'm happy and we have a defeat like yesterday I'm frustrated. But we don't want to be up and down like we're riding a roller coaster."

Moriyasu said he had always "expected it to take three games" to qualify for the next round.

"We've already moved on and we're preparing for the Spain game," he said.

"Whatever the result of the first two games were, you have to think only about the next one.

"We've thought about what went wrong and we're looking to turn that into energy for the Spain game."

Moriyasu also knows the size of the task his players are facing against a Spain team that has scored eight goals at the tournament so far.

"They're able to use their technique even when the game is hard and fast, passing the ball between themselves," he said.

"They're the best team in the world at doing that."

Spain have not yet clinched their place in the knockout round and would go out if they lose to Japan and Costa Rica beat Germany.