Russia moved to within a step of winning a ticket to next year's Beijing Olympics as they powered past Puerto Rico in the men's World Cup volleyball.

The Russians coasted to a 25-22, 25-21, 25-19 victory for an eighth straight win in the 12-team round robin competition in which the top three finishers will qualify for the Olympics.

But Russian coach Vladimir Alekno was not satisfied with his team's performance.

"It was not because we under-estimated Puerto Rico, but I'm already thinking about the last round in Tokyo. It is very difficult to say whether we are playing our 100 percent or not," said Alekno.

"All I can say is that we have dropped only one set in eight games and produced a series of good results. Now we must be stronger mentally for the Tokyo round."

In Tokyo, Russia will play Bulgaria on Friday and Brazil on Saturday, and one win over either of them will be enough to qualify for the Olympics.

Argentina defeated African champions Egypt 25-22, 25-19, 16-25, 25-21, while European champions Spain outclassed Japan 24-26, 25-19, 25-18, 25-19.

In Okayama, world bronze medallists Bulgaria fended off an unexpectedly tough challenge from Tunisia to win 26-24, 22-25, 25-15, 25-17, while the United States powered past Asian champions Australia 25-17, 25-12, 25-19.

World champions Brazil were straightforward 25-20, 25-17, 25-20 winners over South Korea for a 7-1 win-loss record.

US captain Thomas Hoff appeared confident before playing Japan, Bulgaria and Russia in the final three days.

"We're getting stronger, we're comfortable with the playing schedule and each day we are getting better," said Hoff.

"Today was an exceptional match for us. There was no area where we were deficient. We executed at an extremely high level. Hopefully, we can continue this into Tokyo," he added.

Meanwhile, Bulgarian coach Martin Stoev predicts his team will earn a better points ratio than the United States.

"We wanted to win with a big points difference but it was obvious my players were under pressure. I hope we can recover in the two rest days. In Tokyo, for us and the United States, the tournament starts again," he said.

Both Bulgaria and the United States have a 6-2 record, trailing Russia and Brazil.

AFP