New Zealand and Fiji, who have played some epics in deciders at this tournament, won contrasting semifinal victories in wet conditions as the event toasted 40 years.
Fiji were untroubled to defeat Australia 34-5, but the All Blacks Sevens snatched victory with a dramatic double extra time try to Regan Ware after a spluttering attacking effort bedevilled the first 14 minutes of their clash with South Africa.
Despite some shoddy passing and lethargic attack, they headed South Africa 12-7 in a rugged clash. The Blitzbokke's search for an elusive Hong Kong title thus continues.
Neither Sonny Bill Williams nor Liam Messam could make much of an impression in the big matches and indeed were quiet over most of the weekend.
Earlier in the day, New Zealand had defeated Wales 19-7 in the Cup quarter-final, mainly thanks to a fine hat-trick to Kurt Baker, who seems to come up with these big plays when required.
South Africa narrowly won the third-fourth playoff, 14-12 over Australia. So New Zealand will leapfrog South Africa into second place on the log with three legs still to play.
The next World Series event is this weekend in Singapore.
• Australia have won their third straight women's World Series Cup decider, defeating a depleted New Zealand 24-19 in the Atlanta Sevens in a victory that was more comfortable than the final margin would suggest. Selica Winiata scored a brace, but Australia's 19-0 early lead was telling. Australia lead New Zealand by 14 points after three legs. The next tournament is slated for this weekend in Langford, Canada.
Fiji 21 (Jerry Duwai, Kitione Taliga, Semi Kunatani tries; Osea Kolinisau 3 con)
New Zealand 7 (Pita Ahki try; Gillies Kaka con) HT: 7-7