A brace of tries by the hotstepper Rosko Speckman highlighted the Blitzboks' opening salvo in defence of their Dubai Sevens title as they dispatched Zimbabwe 31-0.
Star playmaker Justin Geduld has been ruled out of the rest of the tournament after picking up an unspecified injury on Friday.
Geduld was replaced on the field by Dewald Human during the second half, and did not return to the field.
The second leg is next weekend in Cape Town.
New Zealand won the Dubai Sevens title a record-tying sixth time after beating first-time finalists the United States 21-5 in the Cup final on Saturday.
Storm Diana to bring gale-force winds to Preston
Dry in many places at first tonight, but spells of wet and windy weather will spread from the southwest later. Dundee and the local area has been placed under a flood alert as the country braces itself for Storm Diana.
In the rematch, New Zealand took a 7-0 lead, but the USA capitalized on a penalty to make it 7-5.
Watch highlights from the HSBC World Rugby Sevens tournament in Dubai, including the Canadian women's silver medal win.
The top four teams at the end of the World Series season will automatically qualify for the 2020 Olympic Summer Games in Tokyo. It was the Eagles' first time reaching the Dubai sevens final and thus their best finish in the prestigious season opener. Team USA finished sixth past year.
Canada now sits second in the World Series Standings behind New Zealand.
Tyla Nathan-Wong scored two tries and kicked three conversions against Canada to be named Player of the Final, while Sarah Goss won Player of the Tournament honours.
New Zealand are in a pool alongside Ireland, Russia and Kenya, while the third and final pool features Canada, France, Spain and Fiji. That will be followed by the Japan Sevens from April 20-21 in Kitakyushu, Canada Sevens from May 11-12 at Westhills Stadium and Paris Sevens from June 7-9. New Zealand faced England overnight in the semifinals. The All Blacks pushed ahead, however, after a lineout to make it 14-5 and then surged ahead with a try in the waning minutes to seal the victory.