The Blitzboks scored two tries against New Zealand to win the USA Sevens Cup final 14-7.
Scott Curry was the first to strike and scored the opening try following a good build-up from New Zealand.
Branco du Preez then scored on the stroke of half-time, only a minute after the scrumhalf returned to the field following a concussion test from an earlier knock, to level the scores at 7-7.
Werner Kok scored South Africa's second try, capitalising on a steal from a New Zealand lineout. The Blitzboks then had to hold out a concerted New Zealand attack to secure their second sevens tournament in a row and their third Las Vegas Cup in four years.
Canada won the third-place play-off against Samoa, while England won the Plate, Fiji won the Bowl and the United States won the Shield.
South Africa 14 Samoa 0
In the semi-final against Samoa, Chris Dry was the only scorer in the first half, taking a quick tap-penalty and using his strength to take on the Samoan defence and stretch out to score after the hooter had blown for half-time.
The second half saw Sampie Mastriet slice through the defenders to score South Africa's second try, but he injured his hamstring while sprinting the final stretch.
The Blitzboks then endured some powerful attacking phases from the Samoans, but were able to wind down the clock to close out the game.
South Africa 36 Argentina 0
In their quarter-final, Cecil Afrika scored first from a well-executed set piece. Seabelo Senatla used his fast footwork to grab the second try, side-stepping through the Argentinian defence. Senatla also assisted a try for Branco du Preez to make the score 19-0 at half-time.
Dry opened his Vegas account in the second half with two tries, and Werner Kok also added to his try-tally for the tournament.
Photo: Isaac Brekken/AFP Photo