US thrash Puerto Rico 106-42

Holders the United States hit the century mark against Puerto Rico on Friday to signal they mean business at the women's basketball World Cup while Serbia upset Olympic silver medallists Japan.

The three-time defending champions romped 106-42 in Sydney to make it 2-0 in Group A as they target an 11th title, after easing past a strong Belgium on the opening day of the 10-day championships.

The Americans shot 54 percent from the field with Shakira Austin (19), Kahleah Copper (18), Brionna Jones (13), Jewell Loyd (12), Breanna Stewart (11) and Alyssa Thomas (11) all in double figures.

"Defensively, again, led by Alyssa with six steals, I think we were just really hard to play against," said coach Cheryl Reeve. "We also had a bench that was really, really good."

It was their 24th consecutive win at the World Cup, stretching back to 2010.

Thomas said the score didn't properly reflect what they had achieved.

"We were working on our team chemistry and we added a lot of new pieces," she said. "Games like this are helpful."

Puerto Rico won their first-ever World Cup game on Thursday when they crushed Bosnia and Herzegovina 82-58.

But they were no match for the mighty Americans, who blunted the dangerous Arella Guirantes.

Guirantes scored an incredible 26 points, nine rebounds and eight assists in that Thursday win, but was restricted to just seven points in her near-20-minute court time.

"Today we didn't show up. We were playing the best team in the world, but I think we didn't try," said Puerto Rico's disappointed coach Jerry Batista. "We must learn from this. We have to be more aggressive."

Ominously, the Americans were again not even at full strength.

The Las Vegas Aces' Chelsea Gray, Kelsey Plum and A'ja Wilson arrived in Sydney jet-lagged early Friday after their team sealed the WNBA Finals last weekend, so they took no part.

Asian champions Japan poured in 16 three-pointers in their 89-56 thumping of Mali in Group B on Thursday, but managed just five from 22 against Serbia -- and it cost them.