|Bryan Habana of the Springboks scores his team's opening try during their victory over Samoa [GALLO/GETTY]
South Africa demonstrated the defensive skills that made them world champions as they held off a spirited Samoa 13-5 in a bruising and entertaining clash on Friday to reach the World Cup quarter-finals.
Samoa enjoyed the majority of possession in front of a capacity crowd at the North Harbour Stadium but the Springboks were physical in the tackle and clinical in attack to end the Pacific Islanders hopes of reaching the last eight.
Winger Bryan Habana scored an early try and Frans and Morne Steyn kicked eight points between them as the Springboks made it four wins from four to win Pool D and set up a probable quarter-final against Australia.
Both sides finished with 14 men after Samoan fullback Paul Williams was shown a red card in the 69th minute for striking flanker Heinrich Brussow while Springbok replacement John Smit was given a yellow card for a deliberate knock on shortly after.
"It was really tough," said South Africa's Victor Matfield in a pitchside interview.
The match had been expected to be full of hard hits and physical play and neither side disappointed with some huge collisions in the opening stages.
South Africa started strongly and instigated a number of mauls early to suck in Samoan defenders and the tactic resulted in the opening try.
After a Springbok maul had marched deep into Samoan territory, the South Africans sprayed the ball right and then left with winger Habana squeezing in the corner for the try.
Morne Steyn converted from the touchline but it was Frans Steyn's prowess with the boot that was earning bigger praise, the inside centre landing a 55 metre penalty in the 25th minute to stretch the lead to 10-0.
Samoa were growing frustrated as they struggled in the set piece with their lineout faltering, the scrum under pressure and unable to stop the Springboks pilfering ball at the breakdown.
Ill discipline from Samoan lock Kane Thompson brought a penalty 10-metres closer to his posts and Morne Steyn stroked over another kick to stretch the lead to 13 at halftime.
Habana then limped off early in the second half for the Springboks as Samoa began to find their attacking groove and pressed for a try to get them back in to the match.
The Springbok resistance finally caved in the 51st minute when Samoan number eight George Stowers crashed over for a try after picking up a loose ball following another crash-bang, attacking move.
| Samoan players salute the crowd after impressive display against the Springboks [GALLO/GETTY]
The try spurred the Samoans on as they improved in the set piece and, roared on by a passionate crowd, they slowly made more and more holes in the Springbok defence.
Inside centre Eliota Fuimaono Sapolu and winger David Lemi both threatened to score tries as Samoa threatened an unlikely comeback before Williams was sent off in the 69th minute.
Springbok flanker Brussow repeatedly struck Williams on the arm as the fullback, lying on the floor, hung on to his shirt and prevented him from leaving a ruck. The Samoan then got to his feet and slapped the South African who fell to the ground with referee Nigel Owens showing a red card after consultation with his assistant.
It was soon 14 aside, with Smit shown a yellow card which ended his game after palming for an intercept pass he was never going to reach before kicking the ball downfield.
Samoa continued to press but the Springboks held firm to deny the Islanders the point they needed to maintain their hopes of finishing runners-up in Pool D.
Wales need just a point from their match with Fiji on Sunday to join South Africa in advancing from Pool D.