South Africa recorded a 29-14 win over Argentina in the Cape Town Sevens for a third successive tournament win on home soil.
The Springboks defeated Australia in the quarter-final and France in the semi-final, before facing Argentina who were taking part in their first Sevens final since 2009.
Argentina had beaten New Zealand and Kenya in their quarter-final and semi-final respectively, and though they took the lead in the final, fell short of the mark as the experience of South Africa shone through.
German Schulz opened the scoring went over after some sharp play from Fernando Luna, and the conversion gave Argentina a 7-0 lead.
Rosko Speckman cut the deficit to 7-5 before tries from Seabelo Senatla and a second from Speckman gave the home nation a 17-14 lead.
The South Americans kept in touch through an Axel Muller score under the posts, but South Africa then broke free through Senatla's second try of the match and a final effort from Ryno Banjamin on the back of clever work from Cheslin Kolbe.
A 14-12 defeat at the hands of Kenya in the pool stages ignited a stern response from South Africa on the second day, according to coach Neil Powell.
"The guys decided after yesterday to pull together and start playing rugby," said Powell. "I'm really proud of them today.
"You have to work for everything, nothing is given to us and Argentina put us under lots of pressure."
South Africa had also won the 2013 and 2014 titles when the event was staged in Port Elizabeth.
"The way the anthem was sung and the noise they made when we had our first line-break was just incredible," said captain Kyle Brown. "That really lifted us."
France, beaten 21-12 by the hosts semi-final, took third place with a 28-26 win over Kenya.
The third round of the world series takes place in Wellington from January 30.