TOKYO- Top-seeded Serbia remained perfect in the Olympic men's 3x3 basketball tournament on Sunday, while the Japanese women shocked the heavily favoured French team.

3x3 basketball has seen numerous upsets in its Summer Games debut, but the dominance of Serbia has held firm. The four-man squad led by Dusan Domovic Bulut beat Poland and a tough Belgian side on Sunday to stand alone at the top of the men's division with a 4-0 record.

"We were not team mates before this, so I think every game we can play better and better," said Bulut, the first real superstar. "We are still exploring each other and what we can do."

The Japanese women dispatched winless Mongolia before holding on to beat France 19-15 in the evening. Scoring was nearly even among the Japanese players, who utilised quick passing and timely two-pointers to surprise their top-ranked opponents.

"I think a strength of the Japanese team is that we cover for each other and score points together to make up for where we're not as strong," said Mai Yamamoto, who forced a turnover with 22 seconds left to allow her team to run out the clock.

The Mongolian women, winless so far, were cheered on by Prime Minister Luvsannamsrain Oyun-Erdene, one of few dignitaries to make it to the scaled down Games due to the COVID-19 pandemic.

French President Emmanuel Macron and U.S. first lady Jill Biden attended a game between their countrywomen on Saturday as 3x3 basketball made its Olympic debut.

Italy overcame Romania 22-14, with Raelin D'Alie an impressive five-for-five from the two-point line. But D'Alie's heroics weren't enough to overcome the Chinese women's team, who went repeatedly to 6'5" Zhang Zhiting for hoop-side buckets, defeating Italy 22-13. Italy is now 2-2 in the tournament, which features eight teams each for the men and women.

With an Olympics debut, 3x3 is looking to boost its global profile as a faster-paced, more compact alternative to basketball.

DJs play hip-hop music throughout competition 3x3 games, in keeping with the sport's urban roots.

The medal matches will take place on Wednesday.

(Reporting by Rocky Swift; Editing by Peter Rutherford and Ed Osmond ) ((rocky.swift@thomsonreuters.com;))