Stumps Australia 390 and 33 for 0 (Maddinson 17*, Head 10*) lead South Africa 284 (Bedingham 49, Cummins 3-54, Hazlewood 2-54) by 139 runs
Pat Cummins and Steven Smith produced outstanding performances to overwhelm a lacklustre South Africa batting line-up on day three in Durban before new opener Nic Maddinson enjoyed a confidence boost as Australia gained a stranglehold of the opening Test.
After claiming a first-innings lead of 106 runs, Australia were 33 for no loss in their second innings with Maddinson unbeaten on 17 and Travis Head on 10. Only 5.4 overs were bowled in the innings before bad light stopped play for the third straight day.
When the innings started, all eyes were on Maddinson, who had a disastrous return to Test cricket with a 33-ball duck in the first innings. But he swaggered to the crease and cracked a pull shot to the boundary off Marco Jansen on the first ball of the innings - his first Test runs since December 29, 2016.
Maddinson, whose three previous Tests were all in late 2016, smashed another boundary later in the over before flicking Wiaan Mulder for six over deep square-leg.
Australia are in the box seat - which seemed unlikely when they struggled with the bat on the opening day - but will be wary of bad light potentially restricting days four and five too.
Brilliant bowling and fielding on day three suffocated South Africa, who appeared set to be bowled out before tea until a rearguard from Keshav Maharaj and Simon Harmer halted Australia's push. They enjoyed a 52-run stand before Maharaj added to South Africa's list of tame dismissals when he gifted Mitchell Starc a second wicket, hitting straight to cover.
Harmer and Anrich Nortje added a valuable 35 more for the tenth wicket to eat into the deficit but it wasn't enough to mask a rough batting effort from South Africa, who lacked application and discipline in their first Test match in almost a year.
Cummins spearheaded Australia's attack, consistently challenging the batters as he regularly hit speeds of 140kph and above. He finished with 3 for 54 from 15 overs, with all four frontline Australia bowlers taking at least two wickets.
Smith backed up the bowlers by claiming four catches, which lifted him past Joe Root for the most Test catches by a non-wicketkeeper.
His first three were sublime. With great anticipation, Smith moved into position to snare skipper Temba Bavuma, who had unfurled a reverse-sweep off Nathan Lyon. Smith then pulled off a stunning catch to dismiss David Bedingham, diving across first slip - it was the record No. 221 of his Test career. He saved his best for the third, again moving quickly as he plucked an outrageous one-handed catch off Kyle Verreynne's attempted reverse-sweep off Lyon.
It was a disappointing batting display by South Africa, who started both sessions strongly before losing wickets in clumps. There was little resistance other than Bedingham and Aiden Markram's 84-run second-wicket partnership, while Mulder and Tristan Stubbs put on 56 runs for the fifth wicket.
Bedingham seemed at ease after being elevated to No. 3, a position he had never previously batted at in Test cricket, but was left frustrated after falling for 49 - the top score in the innings.
After a wretched day two, where their attack was helpless against an impregnable Matt Renshaw before the late wicket of opener Ryan Rickelton for a duck, South Africa had looked to bat for the long haul in perfect conditions.
The Kingsmead surface had flattened, with little of the extra bounce and movement that proved quite difficult for Australia's batters on the opening day still in play. With a day of toil in the field looming, Australia aimed to strike with what was still a new ball after only 8.4 overs were bowled when bad light cut short day two.
Resuming at 27 for 1, South Africa started well with the runs flowing off the bats of Markram and Bedingham under sunny skies. But they were never confident against Cummins, who was only four deliveries into his first spell before day two ended.
On the day, he had a big lbw shout against Markram turned down, and he wisely did not call for the review with replays showing the ball was heading over the stumps. He then conjured steep bounce when he had Bedingham in a tangle, but the leading edge flew over the slips for a boundary.
Markram loomed as a key having saved some of his best performances against Australia, averaging over 60 from five previous Tests compared to his career mark of 35.5. He moved to 37 until a loose stroke saw him edge a 144kph length delivery to first slip, with Starc's decision to bowl around the wicket proving a masterstroke.
Having entered the attack 40 minutes into the day's play, Lyon found his groove right away, which was a far cry from his South Africa counterparts Maharaj and Harmer, who were counter-attacked in Australia's first innings.
South Africa's scoring stalled and the pressure took its toll on Bavuma, who made just 3 from 27 balls before falling to Lyon.
Just before lunch, Lyon thought he had taken a second wicket when Mulder edged to Marnus Labuschagne at first slip, but third umpire Richard Illingworth deemed the ball had touched the turf.
Mulder was out to capitalise after the interval and combined well with Stubbs to steady South Africa. Lyon was unable to rediscover his accuracy, while the introduction of Head's part-time spin did not pay dividends with Mulder smashing his first ball into the grassbanks over square leg.
Right when Australia needed a spark, Cummins stepped up like he has done on so many occasions. He bent his back and conjured extra bounce to deliver a 143kph bouncer that bamboozled Mulder, who tried in vain to get out of a pull shot, only to hit straight to midwicket.
Cummins then completely outwitted Stubbs with a short-ball tactic that had the impatient batter holing out to deep fine-leg. His stranglehold over South Africa's batters finally eased when he tired late in the spell as Jansen counter-attacked with a trio of boundaries in the space of five balls.
But Jansen's flurry was all too brief as he tamely hit Josh Hazlewood to mid-off in a poor dismissal. Although perhaps he was still in a daze having moments earlier watched from close range Smith's unbelievable catch to dismiss Verreynne.
