South Africa fullback Cheslin Kolbe scored two tries to lead his team's seven-try attack and flyhalf Handre Pollard added 14 points on four conversions and two penalty goals as the Springboks trounced Italy 49-3 on Friday at Shizuoka Stadium Ecopa.
South Africa (2-1) earned five points and is tied for the Pool B lead with Italy (2-1), followed by New Zealand (2-0), which takes on Namibia on Sunday at Tokyo Stadium.
"I'm just happy. This was a crunch game for us. It looked easy but it was a fairly slippery game for us," South Africa coach Rassie Erasmus said. "The players are obviously now in playoff mode. Our team understands that we're under pressure and we've accepted that now and we're going to live by that now for the next couple of weeks.
"We were clinical. Italy's a great contesting team at lineouts, I thought our lineouts were great, I thought (our) scrums were great."
A win would have given Italy a quarterfinal berth, but the Europeans' hopes of advancing to the World Cup quarterfinals for the first time were put on hold.
In their first-ever matchup in the World Cup, South Africa overwhelmed the Italians with tight defense and powerful scrums. Italy lost prop Simone Ferrari to an injury one minute into the game, and that hurt its offense.
Kolbe opened the Springboks' scoring as he received a pass from fullback Willie le Roux to cross the goal line 5 minutes into the game. After exchanging penalty goals, South Africa held the Azzuri scoreless the rest of the way.
Mbongeni Mbonambi improved the number of tries he scored in this World Cup to three as he dived into the goal area off a powerful scrum en route to a 17-3 halftime score.
Less than three minutes into the second half, Italy's prop Andrea Lovotti received a red card for rough play and was ejected. The Springboks took advantage of the loss by deploying their passing offense effectively and using the field horizontally as well.
Kolbe's second try occurred after a kicking pass to the outside, and Lukhanyo Am picked off the Italian's passing error for a try. Malcolm Marx's try in the 83rd minute ended a seven-try rally.
"Obviously for us, as outside backs, to get the ball out wide and run with the ball is exciting," Kolbe said. "I have to give credit to all the boys for all the hard work and just sticking to the game plan."
Italy coach Conor O'Shea said his team was overpowered by South Africa.
"South Africa was massive and powerful," O'Shea said. "You can't play 40 minutes with 14 players."