South Africa 158 for 7 (Miller 53*, du Plessis 40, Coulter-Nile 3-29) beat Australia 157 for 9 (Finch 40, Tahir 3-21) by three wickets
Scorecard and ball-by-ball details
David Miller struck his first international fifty since February last year and his career-best T20I score to guide South Africa to the highest successful chase at Kingsmead and a lead in the three-match series against Australia. Miller's return to form came at an opportune time - South Africa were 95 for 6 in their reply and needed a lower-order surge to ensure their efforts with the ball were not wasted.
On a dry, cracked pitch, they pulled Australia back in an innings that was destined for over 200. Imran Tahir led the strangle to pull Australia back from 69 for 1 in the PowerPlay. South Africa took 6 for 45 between the sixth and 16th over and not even Mitchell Marsh's cameo at the end gave Australia enough to defend.
Neither side will be entirely happy with their batting performance but Australia will have cause to question their composition more. For the first time in T20I cricket, they chose to bat David Warner down the order and used Aaron Finch and Usman Khawaja upfront and may reconsider that going forward.
Finch's aggression was obvious was from the start. He took on Kagiso Rabada in his opening two overs but South Africa regained some control when Rabada removed Usman Khawaja.
Instead of keeping Rabada on, du Plessis gave the ball to JP Duminy and Finch had a field day. He sent the first three balls for six over deep midwicket and the fourth delivery bounced just a few metres short of the deep cover rope. Duminy's over cost 24 runs and gave the early advantage to Australia.
Chris Morris did not fare too much better with an opening over of 15, as he veered between short and full and Warner used placement over power to cash in. David Wiese, who could have bowled with the fielding restrictions in place, was brought on immediately after they were lifted and had success by having Warner caught at backward point to stem the tide. Imran Tahir, who could also have bowled in that period if du Plessis felt he needed spin, came on in the next over and had Finch caught off a full toss to remove the biggest threat.
Tahir should have added Glenn Maxwell with the next ball but Quinton de Kock, who had taken over the keeping duties from AB de Villiers, spilled the catch. Maxwell lasted for long enough to see his captain, Steven Smith, scratch around and then edge Wiese to de Kock and then tried to hit Morris over cover but got a leading edge which du Plessis snaffled.
South Africa would have felt they were into the lower order with Peter Nevill, the specialist gloveman, at the crease and even more so when Tahir trapped him lbw and bowled John Hastings with a googly in his next over. Australia had tumbled to 114 for 7 and South Africa were in control.
Marsh struck the ball cleanly to ensure Morris' figures did not improve and even got stuck into Kyle Abbott. He finished with 35 off 25 balls when he fell in the final over to give Australia a fighting chance.
They were off to the perfect start when Nathan Coulter-Nile had AB de Villiers caught behind off the first ball of South Africa's reply. With Hashim Amla sitting out, South Africa seemed vulnerable, more so when Quinton de Kock misread the slower ball and offered Coulter-Nile a return catch.
Australia copied South Africa's approach and used their back-up spinner, Maxwell, in the PowerPlay and du Plessis tried to do as Finch did. He took 16 runs off Maxwell's over but South Africa were set back again when Duminy picked out midwicket. South Africa were 45 for 3 at the end of the PowerPlay.
Marsh and Adam Zampa kept South Africa quiet before Marsh removed Rilee Rossouw and next ball du Plessis was run-out, as Nevill completed a sharp piece of work after running round from behind the stumps, to leave South Africa 73 for 5 at the halfway stage with only the lower order to come.
Miller was the striker again when Wiese charged down for a single that was never on and it was left to Miller and Morris to win the game.
Both regard themselves as finishers. Morris has proved himself in the recent limited-overs matches against England, but it was Miller who took on the task of winning the match this time. He was particularly severe on Andrew Tye. His two sixes in Tye's third over brought South Africa's requirement down from 45 off 30 balls to 29 off 24.
Morris fell in the next over - Finch taking an excellent running catch - but Miller kept going. He sent Hastings through the covers and over deep square leg to leave just ten to get off the last two overs. Fittingly, Miller and his Dolphins team-mate Abbott were at the crease and after Miller brought up his fifty off 33 balls, Abbott hit the winning runs.