SYDNEY, Australia (AFP) — Holder the United States hit the century mark against Puerto Rico on Friday to signal it means business at the FIBA Women's World Cup while Serbia upset Olympic silver medalist Japan.

The three-time defending champion romped 106-42 in Sydney to make it 2-0 in Group A as it targets 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," coach Cheryl Reeve said. "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 its 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 Women's National Basketball Association Finals last weekend, so they took no part.

Asian champion 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.

The Serbs raced to a 24-9 lead in the first quarter before Japan woke up, but the margin was too great and they slumped 69-64.

Jovana Nogic led the way for Serbia with 13 points and nine rebounds, making amends for the team's 67-60 loss to world No. 4 Canada in the opener.

The top four teams from each of the two groups progress to the quarterfinals.

Belgium is aiming to bounce back from its defeat to the USA by beating South Korea later, a team struggling without marquee star Park Ji-su.

Bosnia and Herzegovina will look to recover from their shock defeat to Puerto Rico against China, which crushed the Koreans 107-44 first up.

Host Australia, the beaten 2018 finalist, takes on Mali as it attempts to get back on track after crashing to France.