The United States gathered momentum with a win over Greece at the Basketball World Cup on Monday, while there were historic first victories for debutants South Sudan and Cape Verde.

Defending champions Spain, Serbia, and a Luka Doncic-inspired Slovenia picked up their second wins of the tournament, while New Zealand and Cote d'Ivoire got off the mark.

The United States faced a Greece side missing Milwaukee Bucks superstar Giannis Antetokounmpo in their second game in Manila, and they wasted little time in showing their quality in a 109-81 win.

"Our thought process every game is to wear the opponent down," said head coach Steve Kerr.

"We're 12-deep on our roster and we're just trying to stay solid on every possession and really put pressure on the opponent."

Austin Reaves led the United States in scoring with 15 points, followed by Jalen Brunson and Anthony Edwards with 13 each.

The Americans were rewarded with impressive performances throughout the lineup, with the hard-working Josh Hart pulling down 11 rebounds.

"He has the ability to do things on the court as every other NBA player does, but he takes pride in always doing the little things on a nightly basis," Brunson said of Hart, his teammate with the New York Knicks.

"He brings that toughness, that effort, and he's a different man. He goes out there and he's relentless."

Antetokounmpo withdrew from Greece's squad on the eve of the tournament, saying he was not ready to play after undergoing knee surgery last month.

The Greeks can still advance to the next round if they win their final group game against New Zealand, who beat Jordan 95-87 in overtime earlier in the day.

"If we want to have a posibility to win the game against New Zealand, we've got to be more physical," said Greece head coach Dimitris Itoudis.

"For them and for us, it's a final."

Historic wins

Spain also made it two wins out of two, beating Brazil 96-78, while elsewhere in Group G, Cote d'Ivoire beat Iran 71-69.

In Group B, debutants South Sudan stunned China 89-69 for their first ever World Cup win.

The world's number 62-ranked team scored 15 three-pointers on the way to victory in Manila, putting them right in the mix for a place in the next round.

South Sudan head coach Royal Ivey said his players "stuck to the game plan from the opening tip to the closing horn".

"They were resilient, persistent, they had laser-like focus, they followed the game plan and competed at the highest level," he said.

"They played with emotion, they played with fight, they played with fire. We competed all 40 minutes and we came out with the victory."

The result left China needing to beat Puerto Rico in their final group game on Wednesday and hoping that other results go their way to avoid a first-round exit.

China head coach Aleksandar Djordjevic accused his players of lacking "aggressiveness".

"In moments of difficulty, you have to find your spirit to respond on the floor," he said.

"It cannot be everything on paper — you have to find it. Those moments are making winning teams."

Serbia beat Puerto Rico 94-77 to stay in control at the top of Group B.

In Group F, Cape Verde also pulled off their first World Cup win, beating Venezuela 81-75.

The smallest country ever to appear at the World Cup were down by 10 points early in the fourth quarter but took the lead with 57 seconds remaining.

"This is a historical moment for us," said Cape Verde head coach Emanuel Trovoada.

"It's a small nation with a big heart."

Elsewhere in Group F, Doncic scored 34 points and had 10 rebounds and 6 assists as Slovenia beat Georgia 88-67.