The Blitzboks dug deep in their final pool match to secure their passage into the up quarterfinals where they will meet Samoa.
The Blitzboks overcame Canada 31-7 to finish in second place behind Scotland, who claimed top spot in Pool A as they defeated Japan 31-14 to remain unbeaten.
Samoa claimed top spot despite being held to a 19-19 draw by Russia and are joined in the Cup quarterfinals by Fiji, who overcame Australia 31-14 in their final pool match.
New Zealand remained unbeaten in Pool B after they saw off the USA 27-14 in their final pool match. Despite the defeat, USA still advance to the Cup quarterfinal. In the other match, Wales were too strong for Argentina as they walked away with a comfortable 47-28 win.
In Pool C, England secured their passage into the Cup quarterfinals after playing out to a 12-12 draw with Kenya and are joined by France, who easily overcame Spain 33-0.
Scotland 31-14 Japan
It Scotland less than one minute to open the scoring with an unconverted effort but Japan came back to take a 7-5 lead when they grabbed a converted effort in the third minute. But Scotland flexed their muscles in the final minutes of the half to add two converted tries of their own to hold a 19-7 lead at the break.
Japan got themselves back to within five points in the 10th minute when they grabbed their second converted try to trail 14-19. Scotland finished strong once again as they dotted down two scores, one converted, to end the pool phase unbeaten.
Canada 7-31 South Africa
The first half belonged entirely to the Blitzboks as they opened the scoring in the second minute through Chris Dry. Branco du Preez failed with the conversion but it mattered little as Werner Kok doubled the lead in the fourth minute. Du Preez was on target this time as the South Africans took a 12-0 lead. Kok dotted down his second of the match just before the break and despite du Preez' missed conversion, South Africa held a comfortable 17-0 lead at the interval.
Dry got the scoring going in the second half when he scored two quick five-pointers - to complete his hat-trick. Du Preez added both conversions to endure a 31-0 lead. Canada had the final say of the game though as they dotted down for a converted try to have something to smile about.
Wales 47-28 Argentina
Wales got the ball rolling in the second minute with a converted try before doubling their lead in the fourth minute. They then took a commanding 26-0 lead by the seventh minute when they added two further tries, one converted. Argentina hit back in the final play of the half to trail 7-26 at the break.
Wales then extended their lead to 33-7 by the ninth minute, only for Argentina to hit back almost immediately to trail 14-33. Any notions of a comeback were extinguished in the 12th minute as Wales extended their lead to 40-14. Wales bagged another try in between two converted Argentina tries to claim the comfortable victory.
United States 14-27 New Zealand
New Zealand opened the scoring in the second minute with an unconverted effort but the USA hit back immediately to take a 7-5 lead in the fourth minute. New Zealand finished the half in front though as they scored their second unconverted try for a 10-7 lead.
The USA took the lead once again with a second converted try but New Zealand blew them away in the closing stages of the encounter. Three tries, one converted, were scored in the remaining three minutes as New Zealand claimed another victory.
France 33-0 Spain
France struggled to get going in the first half but managed to finally work their way over the try line in the sixth minute with a converted try. There was time for one more score though as they took a 14-0 lead into the break.
The matched waited until the 11th minute for another try as France stretched their lead to 21-0 before bagging another converted try in the 13th minute to extend their lead to 28-0. France closed out the game with one last try in the final minute to claim the emphatic victory.
England 12-12 Kenya
It took England four minutes to break the deadlock when they grabbed an unconverted try but Kenya hit back just before the interval with a five-pointer of their own to head into the break level at 5-5.
England took the lead for the second time in the game in the 10th minute when they dotted down a converted try but Kenya hit back once again to level matters at 12-12 in the 13th minute. That is how it remained as they shared the spoils.
Samoa 19-19 Russia
Russia opened the scoring with two minutes gone on the clock thanks to a converted try but saw their lead become a deficit by half-time as Samoa grabbed two tries, once converted, to take a 12-7 lead at the break.
Samoa came out firing and extended their lead in the 10th minute with another converted try but then had to hold off a Russian onslaught. Russia narrowed the deficit to 14-19 in the 13th minute with their second converted try before bagging a third try in the final play. The conversion would have handed them the victory but it failed to find the target
Australia 14-31 Fiji
Despite being a man down Fiji grabbed the lead in the fourth minute with a converted try. However, Australia hit back immediately to level matters at 7-7. Fiji finished the half on the front foot as they bagged their second converted try to hold a 14-7 lead at the interval.
Fiji extended their lead to 19-7 in the ninth minute with an unconverted try before Australia hit back with their second converted effort in the 12th minute to trail 14-19. But that would be their final feeling of joy as Fiji bagged two further tries, one converted, to claim the victory.
(All times are local. GMT plus two)
09.00 - Canada v Russia
09.22 - Kenya v Argentina
09.44 - Australia v Japan
10.06 - Wales v Spain
10.28 - Scotland v Fiji
10.50 - England v USA
11.12 - Samoa v South Africa
11.34 - New Zealand v France
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