South Africa achieved a bitter-sweet 28-8 Rugby Championship victory over Australia Saturday at Newlands in Cape Town.

The home side finished convincing winners after leading 23-3 at half-time, but scored only three tries to miss the bonus point they wanted to put pressure on title rivals New Zealand.

South Africa did move to the top of the table on scoring differentials, but New Zealand have a chance to go five points clear when they play in Argentina late Saturday

The global rugby giants clash at Ellis Park in Johannesburg next Saturday as the southern hemisphere tournament reaches a climax.

Hopes were high of a four-try triumph when the Springboks scored two within 15 minutes of the kick-off, but they had to wait until the closing stages for the only other one.

"I never thought I would be so disappointed to beat Australia by 20 points," admitted South Africa captain and centre Jean de Villiers.

"Beating a quality Australian side by that margin is no mean feat, but it would have been nice to score four tries and pick up a bonus point.

"Our discipline needs to improve," he noted, referring to yellow cards for lock Flip van der Merwe and No. 8 Duane Vermeulen.

Australia skipper and lock James Horwill said: "There was no lack of effort, but we did not do things the way we wanted to in the early stages.

"However, we are moving in the right direction, working incredibly hard, and our supporters must just have faith in us."

Springbok scrum-half Fourie du Preez, starting for the first time in 23 months, was voted man of the match after a polished display and fly-half Morne Steyn celebrated 50 caps with 13 points.

The Wallabies, who also had two players sin-binned, were always chasing the game after conceding two early tries, but matched the home side in the second half.

Australia were first on the scoreboard with centre Christian Leali'ifano kicking a simple penalty on seven minutes after Vermeulen was caught offside.

But the advantage was short lived as Steyn slotted his first penalty of the match after Horwill did not roll away at a maul.

Wild celebrations followed for most in the near-capacity crowd as the Springboks scored two tries within three minutes to build a 17-3 lead with less than a quarter of the game gone.

Hooker Adriaan Strauss dotted down after 13 minutes, driving over from close range after a skip pass from Du Preez, and Steyn converted.

Full-back Zane Kirchner claimed the second try, but it was a magnificent team effort that originated at a maul deep in green-and-gold territory.

Du Preez set the ball in motion, and a series of skip passes and a great run by centre JJ Engelbrecht breached the Australian defence before Kirchner ran in.

Another Steyn conversion followed by two penalties closed the scoring in an opening half marred by a yellow card to each team.

Wallaby flank Michael Hooper was first to be punished, walking to the touchline after 28 minutes for a dangerous tackle on lock Eben Etzebeth.

Hooper felt hard done by, and so did Van der Merwe after his 40th-minute card for leading with an elbow against left-wing Joe Tomane.

However, French referee Jerome Garces was fully justified in making both decisions after consulting with the television match official.

Bismarck du Plessis, wrongly red carded during a defeat in New Zealand two weeks ago, replaced Strauss to warm applause 10 minutes into the second half.

Australia gained from the introduction of Will Genia for Nic White at scrum-half and were proving much more stubborn opponents as the second half wore on.

South Africa had to do their share of defending and as the Test reached the final 10 minutes, a four-try bonus point seemed a distant dream.

It did not help the Springbok cause that Vermeulen became the third player to be yellow carded, paying the price for a deliberate knock-on.

But after 40 point-less minutes, South Africa scored a third try eight minutes from time with another superb Du Preez skip pass enabling right-wing Willie le Roux to squeeze in at the corner.

Steyn fell just short with his touchline conversion -- his first goal-kicking failure of the match -- but success was assured with a 25-point advantage.

Replacement forward Sitaleki Timani added to the misery of the visitors by getting a yellow card five minutes from time.

But the side that opened the scoring also closed it with substitute left-wing Chris Feauai-Sautia snatching a late unconverted try.