South Africa, USA into USA Sevens semi-finals

Perry Baker David Becker/Getty Images

LAS VEGAS -- World series leaders South Africa are into the USA Sevens semifinals after beating Australia 29-17 on Saturday.

At the 40,000-seat Sam Boyd Stadium, the South Africans advanced to Sunday's semifinal against Argentina, which beat Kenya 17-12.

In other quarterfinals Saturday, Jerry Tuwai scored the winning try nearly two minutes after the final siren to give Olympic champions Fiji a 14-10 win over New Zealand. The Fijians will play the undefeated United States, who beat England 17-12 behind Perry Baker's three tries.

USA topped Pool C after going through the pool matches undefeated with a huge 28-7 win over Australia, strong 26-12 showing over Samoa and an impressive 28-17 victory over Spain.

But the biggest upset of the tournament so far came with New Zealand falling to Argentina 26-19 in the opening day of play. Currently sitting second on the World Series table New Zealand were expected to easily top their pool, but were only able to secure second spot.

They will now face England for a place in the fifth place final, while Australia will take on Kenya.

South Africa leads the overall series with 77 points after four events, followed by New Zealand (69), Fiji (62) and Australia (60). The Americans are in seventh place with 36 points.

The three-day tournament ends Sunday with Cup and Challenge finals and other playoffs for placings.