Carlin Isles tries his best but USA cede Vegas sevens glory to South Africa

Record crowd sees sprint sensation light up tournament before South Africa beat New Zealand in pulsating final

South Africa won the USA Sevens in Las Vegas on Sunday, beating New Zealand 40-21 in the final after beating Samoa, who won the tournament in 2012, 12-7 in the last four. New Zealand had beaten Fiji 19-14, in extra-time, in the other semi-final.

The event, which was played at the Sam Boyd Stadium over three days, attracted an aggregate crowd of 67,341, 3,000 more than the previous best, which was set last year. On Saturday, a crowd of 31,228 set a single-day record for the event.

The home team qualified for the cup quarter-finals with a 22-7 victory over Spain in their final pool game, in which Carlin Isles, the former college running back and national top-40 sprinter now known as the fastest man in rugby, added two spectacular tries to one scored against Australia. The Eagles were beaten in the last eight by Fiji, 21-19 in a thriller decided by a missed US conversion, the last kick of the game.

Alex Magleby, the USA coach, said: "Credit to the boys. Three of our tries to three of Fiji's tries. The effort was there, and they are playing smarter rugby. It was good to see."

The USA then lost 24-19 in extra-time to Canada in the semi-finals of the plate, one of the consolation competitions for teams beaten at different stages in the tournament. Magleby said: "There is no excuse, that was a game that was always competitive, emotions fly and Canada played well enough to win."

The Canadians completed an encouraging event for north-American rugby by beating Scotland to win the plate; France beat Argentina to win the bowl and Australia beat Uruguay for the shield. The Samoans won another extra-time game, 36-31 against Fiji, in the play-off for third place.

New Zealand are in the overall lead in the HSBC Sevens World Series, of which the American tournament was the fifth stage, with 96 points. They are followed by South Africa with 73, Samoa with 71 and Fiji 66. The US are 13th in the standings, with 28 points from five events.

Each of the tournaments held so far this season has produced a different winner. Fiji won October's first event, the Gold Coast Sevens in Australia, beating New Zealand in the final. Samoa beat the Kiwis in Dubai and New Zealand beat France in South Africa in December before losing to England, who did not get out of their pool in Las Vegas, in their own tournament in Wellington at the start of this month.

The sixth and seventh rounds of the season are in Hong Kong and Japan next month, before the season concludes with tournaments in Scotland and England in May. The Rugby World Cup Sevens will be staged at the Luzhniki Stadium in Moscow on June 28-30; the game will also be included in the 2016 Olympic Games, in Rio de Janeiro.