Fiji beat the Blitzboks 19-7 in the Cup quarter-finals of the London Sevens on Sunday to secure the World Series title.
It is Fiji's second title in the 16-year history of the World Series, and they become the first team other than New Zealand to win it since 2010.
The Blitzboks will finish second on the standings and look back at disappointing tournaments in Glasgow and London with regret. The title was theirs for the taking and they let it slip.
Fiji led 12-0 at half-time of the match that would determine this season's champions, following tries from Savenaca Rawaca and Osea Kolinisau.
Chris Dry's converted try brought the Blitzboks back within striking range, but Rawaca's second try sealed the win for the Fijians.
The Blitzboks went on to beat Scotland 31-7 in the Plate semi-finals before losing 26-14 to New Zealand in the final.
The USA won their first ever World Series tournament when they beat Australia 45-22 in the Cup final.
Blitzboks results (Day 2):
Lost to Fiji 19-7 (Cup quarter-final)
Beat Scotland 31-7 (Plate semi-final)
Lost to New Zealand 26-14 (Plate final)
USA 45 Australia 22
Final World Series standings:
1. Fiji 164
2. South Africa 154
3. New Zealand 139
4. England 152
5. Australia 132
6. USA 108
7. Scotland 89
8. Argentina 80
9. Canada 67
10. Samoa 64
Photo: Christopher Lee/Getty Images