Adelaide: Debutant Rilee Rossouw's fearless 78 has steered South Africa to a seven-wicket win in the first KFC T20 International over Australia at the Adelaide Oval on Wednesday.
Rossouw combined with wicketkeeper-batsman Quinton de Kock (46) for 129-run stand to help the tourists chase down Australia's 144 for 6 with six balls to spare and take a one-nil lead in the three-match series.
Allrounder Shane Watson made a successful return to international cricket with a 36-ball 47, and Pat Cummins claimed 1-21 in his first game for Australia in more than two years.
But with short square boundaries and a true wicket, 145 was never going to be enough as Australia look to regroup ahead of the second T20I on Friday at the MCG.
Australia's innings started with good fortune as both batsmen offered chances to the Proteas fieldsmen, albeit with varying degrees of difficulty.
Cameron White's half-hearted pull presented leg-spinner Imran Tahir a regulation catch at fine-leg, before Finch's full-blooded straight drive caught the outstretched hand of the following-through Kyle Abbott, who did well to avoid injury and stop four if nothing else.
Despite the shaky start, both batsmen were still alive, and Finch refused to stop swinging in the Powerplay overs, blasting left-armer Wayne Parnell for four with a heaving pull stroke.
However, the skipper's luck eventually ran out, mistiming a drive to be caught at cover by Rilee Rossouw off the bowling of allrounder Ryan McLaren, who would be glad Mitchell Johnson wasn't selected for this series after a few painful encounters in Africa earlier this year.
White's intentions failed to waiver, laying back into a vicious pull shot over wide long-on to add four to the score and force McLaren to readjust his lines to the confident Victorian.
In a blink of the eye the Powerplay was done and dusted, honours even at 2-43 after White tried to go up and over point only to pick out the leaping Farhaan Behardien, taking the ball like a Aussie Rules midfielder in the back pocket.
Australia's other debutant had twice as much success with the bat as the other, but Nathan Reardon will rue the attempted upper cut to third man that found the edge and then the outstretched hand of keeper Quinton de Kock.
Watson was joined by James Faulkner - who was released early from Australia's Test tour of the UAE to play this T20 series - and the pair set about rebuilding Australia's plateauing run rate that floated above a run a ball into the 13 over.
Like Jess Jonassen in the preceding T20 clash, Watson and Faulkner decided to go aerial, the former taking on the long straight boundary off Rabada while the latter aimed for the shorter square leg-side boundary off McLaren, escaping with six thanks to Behardien's dropped catch that spilled onto the triangular perimeter rope.
With six overs remaining Australia were yet to reach triple figures (4-97), and by this point they were attacking everything.
A wild swing from Faulkner squirted away to the fine-leg boundary to raise the locals' century and the hushed crowd into relieving applause.
Duminy then gambled with Tahir (1-31) for the leg-spinner's final over, andthe plan spluttered more than backfired, with Watson spanking the leggie over his favoured cow corner for six more.
South Africa were a mixed bag in the field, dropping three catches (one incredibly difficult) and misfielding throughout, but conversely sliding to save ones and twos and hanging onto some spectacular grabs, particularly overhead.
Australia's allrounders put on 57 before Watson (47 off 36) laced Abbott off the front foot to Duminy at deep cover, who did his best Anthony Kelly impression in catching a speeding arrow.
Tight bowling and clever field placings from Duminy tightened the grip on the hosts, who were unable to find the boundary after Watson was dismissed.
Range-hitter Ben Cutting struggled to find the strike and his timing, caught on the long-on boundary to fall for six off as many deliveries, and not even Faulkner could break the shackles, finishing 41 not out with a single four and six next to his name to see Australia grind to 6-144 from 20 overs.
Earlier, Australia have won the toss and have chosen to bat.
Ben Dunk and Nathan Reardon make their Australia T20 debuts while three debut for Proteas -- Rilee Rossouw, Reeza Hendricks, Kagiso Rabada.
Australia: Aaron Finch (Capt.), Cameron White, Shane Watson, Ben Dunk (wk), Nathan Reardon, James Faulkner, Ben Cutting, Pat Cummins, Kane Richardson, Cameron Boyce, Doug Bollinger
South Africa: Jean-Paul Duminy (Capt,), Quinton de Kock (wk), Reeza Hendricks, Rilee Rossouw, David Miller, Farhaan Behardien, Ryan McLaren, Imran Tahir, Wayne Parnell, Kyle Abbott, Kagiso Rabada
Australia - 144/6 (Watson 47, Faulkner 41*, Abbott 3-21)
South Africa - 145/3 (Rossouw 78, de Kock 46)
Result - South Africa won by seven wickets
MOM - Rilee Rossouw (South Africa)