JP Duminy hit a sparkling 67 to provide the backbone for a stuttering South African innings.
Cape Town: Three wickets by debutant Patrick Cummins and a hard-hit half-century by Shane Watson set up Australia for a five-wicket win in the first Twenty20 international against South Africa at Newlands on Thursday.
Fast bowler Cummins, 18, took three wickets in four balls in his last over as South Africa were restricted to 146 for seven in their 20 overs.
Free-scoring Australian opener David Warner was run out for nought off the first ball he faced but Watson (52) and Shaun Marsh (25) put Australia firmly in control during a second-wicket stand of 82 off 53 balls.
Watson survived a straightforward slip chance to Graeme Smith off Morne Morkel when he had two and Australia's total was three for one. Warner had been run out by a direct hit from Morkel at short fine leg in the previous over.
Watson's edge off Morkel ripped through Smith's hands and went for four. He drove the next ball for another four and raced to his fifty off 34 balls with six fours and two sixes.
South Africa's bowlers fought back after Watson and Marsh were dismissed in successive overs, but the tourists were always ahead of the required run rate, even though they only had three balls to spare when Steve Smith hit the winning run.
"We made hard work of it in the end but it's nice to start with a win," said Australian captain Cameron White.
"We were under pressure coming in but it's an exciting team with some new players."
JP Duminy provided the backbone for a stuttering South African effort with a sparkling innings of 67.
Former captain Smith was bowled by Doug Bollinger for a duck and new captain Hashim Amla was run out for four as South Africa struggled to eight for two after three overs after Amla won the toss.
Duminy shared half-century partnerships with Colin Ingram (33) and David Miller (20) but just when it seemed the home side were set for a strong finish, Cummins struck in the 19th over.
Hailed for his ability to bowl at express pace, he took two wickets with slower balls which led to catches from mistimed shots. Duminy and Miller fell off successive balls and Johan Botha went two balls later.
Duminy hit three sixes and six fours in his 53-ball innings.
Amla said South Africa had made some mistakes in the field and were always under pressure after the Watson-Marsh stand.
"We did quite well to take it down to the last over," he said.
The teams will play a second Twenty20 international in Johannesburg on Sunday, before meeting in three one-day internationals and two Test matches.