Japan faces a nervous 24 hours as the Brave Blossoms await the full extent of injuries to Hitoshi Ono and Male Sa'u.

"They have gone to hospital to get checked out and we will know tonight," head coach Eddie Jones said Sunday, the morning after Japan's 26-5 win over Samoa at the Rugby World Cup.

Ono saw his 96th appearance for his country cut short at halftime after he strained his left hamstring, while Sa'u injured his right knee midway through the second half.

There was good news for Jones and Akihito Yamada though, with the wing on the road to recovery after being stretchered off following a knock to the head.

"He is recovering well, though he needs to follow the concussion protocol," Jones said.

Yamada was alert enough after the game, despite losing consciousness on the field, to answer a few questions on the injury and his try.

"I lost it for a moment," he said. "I didn't think I was on the ground for that long. It was only after everyone told me later that I was out for such a long time."

He did, however, remember his try.

"I was pretty sure I would get my chance. It is my first try at a World Cup. I am over the moon," he said.

Jones said he would give his side a fairly easy time of it for the next two days before preparations begin for Japan's final Pool B game against the United States on Oct. 11.

"It would be nice if we had another mini project after the U.S. game," Jones said referring to the possibility of Japan reaching the last eight, should it win and Samoa beat Scotland on Friday.

"But the only thing we can control is the U.S. game. Everything else is out of our control. So we can't worry about it."