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.

“We came into this tournament knowing we’ve made the semifinal three years in a row, and it was all about taking that next step,” U.S. captain Ben Pinkelman said. “So we’re just going to come out, stick to our game plan and hopefully we will be able to make it all the way to that Cup.”

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.