If Temba Bavuma was decisive for South Africa as he batted through day after day in Gqeberha, his fall in the shadow of stumps on the third day might prove as decisive at Cape Town. Bowled by a Nathan Lyon classic with eight balls to go, he saw his team reach stumps at 140 for 4, with a lead of just 40 to build on. Australia had started the day at 330 for 4, their lead exactly 100 by the time they were bowled out for 429.

It was Josh Inglis and Alex Carey resuming a partnership at 145, calmly adding another 40 while sleepy South Africans gave up boundaries with misfields. A peaceable surface and a sunny morning had the Australian pair set to go large, especially with Kagiso Rabada not allowed to bowl for seven overs due to time spent off the field.

Related: Australia strike late to restrict South Africa to 140-4, just 40 runs ahead, on the third day of men’s third Test– as it happened

Somehow, though, this series always has Simon Harmer in the thick of things, a grizzled competitor from the English county game making the most of his late-career Test renaissance. First he nearly pulled off another screamer at slip, one-handed and low to an edge from Carey in Rabada’s first over, pace on the ball ripping open the fielder’s middle finger.

Then, after taping up the wound on his non-bowling hand, the off-spinner was asked to take the next over. The first ball saw Inglis crunch a reverse sweep for four to celebrate a century, but the sixth drew him into a defensive push to be caught behind for 102. Two overs later, Harmer had the left-handed Carey do the same to slip for 80. A less polite individual might have considered raising that bandaged finger to the opposition.

It had been a mighty innings from Inglis, coming off injury, in the side for the first time in nearly a year. For the time being, at least, he is one of only six players in history with two centuries and no fifties, and two tons in a six-Test career indicates that he belongs in this side on a permanent basis. What configuration will permit that is a future headache for selectors.

With Australia’s lead at 50 when Carey fell, much was in the balance. Twice the previous day, South Africa had been unable to turn a double strike into further wickets; here, they made it a triple as Pat Cummins was trapped lbw, a narrow umpire’s call on leg stump going Rabada’s way.

It was a tough gig for Cooper Connolly at number seven, newly arrived both at the crease and more broadly in Test cricket. Matt Renshaw in Durban had joked about telling off Nathan Lyon for aggressive shots, but it’s hard to imagine a 23-year-old in his second Test assuming the seniority to marshal the tail.

Yet to a point he did, batting up to lunch and beyond, collecting singles and twos, working towards doubling that lead. He was badged viciously by Marco Jansen, ducking into the short ball and half turning his head as it crashed into the front of his helmet, but continued to play bouncers with confidence, riding the next ball off his armpit and down past short leg.

Mitchell Starc was caught behind driving Gerald Coetzee, Lyon edged Wiaan Mulder’s outswinger to Harmer, and when Connolly finally had a swing, he smacked one back to Jansen. His 29 won’t break any records, but he had overseen another 50 runs since losing Cummins.

Early in South Africa’s reply, Aiden Markram cover-drove loosely at Starc, letting Head make up for the catch he dropped off the same combination in the first innings. David Bedingham made another poor choice to hook, caught at long leg. Marques Ackerman made his second half-century for the match with 62, again free-scoring with risky pulls through fine leg and slashes through the cordon, wiping off most of the deficit with Bavuma’s quiet support.

But this has been a match for Starc interventions, and with the score on 95, venomous bounce from around the wicket, lefty to lefty, he smashed Ackerman in the grille so hard that it ricocheted to slip. Ackerman saw so little of the ball that he didn’t know he’d edged his pull shot on the way through, eventually challenging the umpire, but he had taken too long. Not happy at being told the clock had run out, that refusal saved his team a review.

Late-day tension rose each over. In a fierce Cummins spell, Matthew Breetzke edged him just short of Renshaw at slip, while Bavuma gloved a nasty one over leg gully. Lyon was getting increasingly serious turn. And with the shadow of a silly mid-off stretched across the pitch, Lyon ripped one back a mile from outside off-stump as Bavuma missed his swing towards leg. In a big day for “effectively”, South Africa are effectively 40 for 4. They won in Gqeberha from there, but it’s a hard search in the clear blue skies of Cape Town to find lightning for a double strike.