TOKYO, Japan -- Japanese superstar Shohei Ohtani hit his first home run of the World Baseball Classic in Sunday's win over Australia, then warned quarter-final opponents Italy that his unbeaten team "can score runs from anywhere".

Facing just his second pitch of the game, Ohtani blasted a huge three-run shot that almost hit an advertising board with his own face on it, to set Japan on their way to a 7-1 win over the Australians.

The victory meant Japan topped Pool B with a perfect four-for-four record and set up a quarter-final showdown with Italy on Thursday.

Ohtani said that hitting a home run at the tournament had been "a dream since childhood" and warned that he is not the only threat in a Japan team packed with talent.

"We can score runs from anywhere and our pitchers are so stubborn," he said.

"We're playing really well but there are strong teams out there waiting for us and I want us to get ready for that."

Japan's early barrage was so fierce that Australia replaced starting pitcher Will Sherriff before the first inning had even finished.

Australia manager Dave Nilsson called Japan the "best team in the world" and said their performance had been "no surprise".

"I think the turning point was when Ohtani hit that ball about 500 feet in the first inning," he said.

"Any time they get a lead early in the game, they're going to be very tough to chase down."

- Pool A chaos -

Japan have assembled a star-studded squad combining the best of the domestic league with major league stars like Ohtani.

Expectation is building that they can win the title for a record third time and manager Hideki Kuriyama said he was "relieved" to clinch a place in the quarter-finals.

"All I was thinking about was getting out of the group and moving on," he said.

"Some of our play was good and there are some things that we still have to work on. First of all, we're moving on and I'm relieved about that."

Australia, who got a consolation ninth-inning home run from Alex Hall, can join Japan in reaching the quarter-finals if they beat the Czech Republic in their final group game on Monday.

They would play Cuba in Tokyo on Wednesday after a chaotic end to Pool A, which was being played in the Taiwanese city of Taichung.

All five teams finished with identical records of two wins and two defeats, but Cuba emerged as group winners with Italy also going through as runners-up thanks to a complicated tiebreaker system.

The Netherlands, who won their first two games, were eliminated after a 7-1 loss to Italy.

Taiwan went out after losing 7-1 to Cuba, while Panama also missed the cut.

In Pool B action earlier on Sunday, South Korea beat the Czech Republic 7-3 to pick up their first win of the tournament.

© Agence France-Presse