The boot of flyhalf Morne Steyn once again carried South Africa to victory as it beat Australia 29-17 in their Tri-Nations test at Newlands in Cape Town on Saturday. Steyn kept the scoreboard ticking over for the Springboks with seven penalties and a drop goal, having scored a Tri-Nations record 31 points last weekend in the win over New Zealand. Australia scored first through fullback Adam Ashley-Cooper in the second minute, but South Africa dominated the second quarter to lead 23-10 at the break. The Wallabies got the only try of the second half, a fine individual effort by flyhalf Matt Giteau but they suffered through indiscipline. Apart from the numerous penalties Australia conceded, referee Alain Rolland showed the yellow card to Giteau and flank Richard Brown in the closing stages of the first half. Loose forward George Smith was also yellow-carded, in the 79th minute, with the Australians desperately defending their line. Lock Victor Matfield scored South Africa's only try after a neat grubber through by tighthead prop John Smit. The Springboks, who beat New Zealand 31-19 in Durban last Saturday and 28-19 in Bloemfontein the previous weekend, have completed an unbeaten home leg of the Tri-Nations ahead of matches in Perth, Brisbane and Hamilton.