Australia's women, playing in yellow, are among the teams go secure their places in the quarter-finals of the 3x3 basketball Olympic qualification tournament ©Getty Images

The top seeds struggled in the men’s and women’s events on the third day of pool games at the International Basketball Federation 3x3 Olympic qualifier in Graz, Austria, as the first quarter-finalists were confirmed.

Men’s top seeds Mongolia, playing in Pool A, lost both of their games today, 21-16 to the Czech Republic, seeded 17th, and 18-10 to ninth seeds Brazil in the final game of the day in the men’s competition.

Third seeds The Netherlands, playing in Pool D, were edged out in the opening game of the day, beaten 17-15 by Canada, seeded 13th.

Fourth seeds Slovenia won their opening match of two today when they defeated Qatar in Pool C 18-11, but were on the end of an upset later in the day when they were beaten 21-17 by Dominican Republic, the 18th seeds.

The highest seed that won both their games today was France, seeded sixth, also in Pool C, as they edged out the Philippines 15-14 and followed it up with a more comfortable 21-10 win over Qatar.

The results ensured France topped their pool as they completed their fourth win from as many matches.

Eighth seeds Poland also recorded two wins today in Pool A edging out Brazil 13-12 before overcoming Turkey 21-10, results that enabled them to top the pool.

In the quarter-finals Poland will take on Slovenia and France will face Brazil.

In the women’s pool matches, the top teams also endured a difficult day with second seeds Iran, playing in Pool B, losing heavily to tenth seeds Ukraine 17-7 and 17th seeds Australia 22-2.

Fourth seeds Italy, competing in Pool D, also lost twice, as they were beaten 21-17 by tournament hosts and 20th seeds Austria, and later 21-13 to 13th seeds Spain.

Fifth seeds Chinese Taipei, also playing in Pool D, were defeated twice, as they lost 22-10 to 13th seeds Spain and 21-11 to 12th seeds Switzerland.

Spain secured a quarter-final place following their surprise win over Chinese Taipei and then beating hosts Austria 21-13, results that helped them top their pool.

They will face Australia in the last four, while sixth seeds Japan, looking to qualify for the sport’s Olympic debut on home soil, will face Switzerland.

Japan secured their place in the knockout stages of the tournament by today beating Ukraine 20-17 and then Thailand 21-6 to top Pool B with four wins from as many matches.

The quarter-final line-ups will be completed tomorrow with Pools B and D concluding for the men and Pools A and C due to conclude for the women.

Three places are up for grabs in both the men's and women's 3x3 basketball competitions at Tokyo 2020 - and these will be awarded to the winners of the men's and women's semi-finals, and the two third placed games.