Las Vegas - South Africa have launched their USA title defence with a pair of impressive victories on the fourth stop of the IRB Sevens World Series on Friday.
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Seabelo Senatla returned from injury to score four tries and Branco du Preez and Justin Geduld registered three tries apiece as South Africa hammered Wales 43-0 in their first Pool A match and followed up with a comprehensive 29-0 victory over Canada.
Coming into the fourth tournament in the series off an emotional victory on home soil last month, South Africa are trying to overtake series leaders New Zealand.
They take on Kenya in their final pool match on Saturday.
Until the 16th and final match of the opening day, all eight quarter-final spots were still up for grabs. But France's narrow 14-12 Pool D victory over the United States sent the disappointed hosts into the Bowl after an earlier 19-12 loss to Argentina.
France, who thumped Spain 47-0, and Argentina, who also beat Spain 33-5, both secured their places in the Cup quarters.
New Zealand, who lead the series with 58 points to South Africa's 56, also won both of their opening-day matches, as did Samoa.
Gold Coast champions New Zealand and Dubai champions Fiji both looked poised to qualify, but Cameron Clark, back in the Australian side after an injury absence, kicked a winning drop goal penalty with the final play of Australia's 22-21 win over Fiji that kept the Pool B race open.
Sam Dickson and Scott Curry both scored in New Zealand's 31-7 win over traditional rivals Australia, while Tim Mikkelson added a brace of tries and a conversion in their 26-5 victory over Scotland.
England fell in their Pool C opener to Samoa 22-19, but came back with a vengeance with a 54-0 rout of Portugal in which captain Tom Mitchell scored 16 points.
Samoa added a 17-12 victory over Uruguay to lead the group on six points, with England and Portugal tied on four.
Uruguay, competing in their first event of this World Series as a non-core team -- fresh from booking their place in March's core team qualifier in Hong Kong -- led two-time USA Sevens winners Samoa 12-5 at half-time before falling.
Results on Friday after the first day of the USA Sevens, part of the IRB Sevens World Series:
South Africa 43 Wales 0
Kenya 15 Canada 17
South Africa 29 Canada 0
Kenya 21 Wales 17
New Zealand 31 Australia 7
Fiji 24 Scotland 0
New Zealand 26 Scotland 5
Fiji 21 Australia 22
Samoa 22 England 19
Portugal 19 Uruguay 5
Samoa 17 Uruguay 12
Portugal 0 England 54
Argentina 19 United States 12
France 47 Spain 0
Argentina 33 Spain 5
France 14 United States 12