Six teams are undefeated after day one at the FIBA 3x3 World Cup ©Getty Images

Six teams are undefeated after the first day of the International Basketball Federation (FIBA) 3x3 World Cup in Antwerp.

Pool stage action began in the men's and women's tournaments in Belgium

The hosts, Serbia, and the United States won both of their fixtures in the men's tournament while Lithuania, Spain, and Canada hold a 100 per cent record in the women's event.

Men's number one seed Serbia did a perfect job of living up to their pre-tournament favourites tag as they beat both New Zealand and Puerto Rico 21-19 in pool A, although they will have been disappointed not be more convincing in victory.

The Tokyo 2020 champions are aiming to build on their record of four titles from six previous World Cups.

Serbian teams have also prevailed in the 3x3 World Tour, winning the first two masters events of the season.

Defending champions US were also in fine form, picking up 21-17 and 22-9 wins against Austria and Slovenia, respectively.

Belgium got off to a good start as they look to break the home ground curse as no host won the World Cup.

They cruised past beat Slovenia 21-16 in a thrilling battle before cruising past Egypt 21-12.

In the women's event, Lithuania beat Japan with ease 21-14 before recording an 18-16 upset against top seed Germany.

Aitana Cuevas was dominant for Spain as they picked up commanding wins against The Netherlands and Chile with respective scorelines of 22-9 and 21-15.

The 35-year-old was the top scorer in both fixtures with nine points in each, helping her to become the most valuable player back-to-back.

Canada beat Chile 21-10 in pool D before obliterating Israel 22-5 in their second match.

Pool stage fixtures continue tomorrow before concluding on June 24 with the tournament then advancing to the knockout stages.