The US were among three countries to qualify for Tokyo 2020 today ©World Rugby

The United States, Fiji and New Zealand booked their places at next year's Olympic Games in Tokyo by reaching the quarter-finals of the World Rugby Sevens Series event in London.

The US became the first team to qualify for Tokyo 2020 as their progress to the last eight at Twickenham Stadium guaranteed their spot in the top four of the overall standings.

The American side, the series leaders, finished in first place in Pool D after winning all three of their matches.

The US beat Spain 29-5 in their opening game before they recorded a narrow 28-26 win over Wales, a result which sealed their place at Tokyo 2020.

They ended their group stage campaign with a 19-17 triumph over Australia.

The US, who are seeking their second victory of the series, will play Canada in the quarter-finals.

Fiji also progressed with a 100 per cent record as they topped Pool B.

The Olympic champions began with a 24-17 win over Kenya before they ousted France 31-10 and Samoa 26-17.

Fiji will go up against Ireland in the last eight.

South Africa were the other team to seal a quarter-final berth unbeaten as they secured top spot in Pool A.

The Blitzboks were in destructive form today, thrashing Japan 49-0 to begin their pursuit of the London Sevens title in style.

A 45-14 victory over Canada saw them continue their high-scoring exploits before they rounded off the group phase with a 40-21 success against Argentina.

South Africa's opponents in the quarter-finals will be Australia.

New Zealand, who overcame Scotland 21-7 and Ireland 34-7 but lost 17-12 to England, topped Pool C and will face France in the last eight.