Australia’s chances of winning their series against world Test champions South Africa soared on the third day of the decider against South Africa at Newlands on Thursday.

South Africa were reeling at 140 for four at the close, just 40 runs ahead with six wickets remaining.

“It’s really satisfying,” said Australian centurion Josh Inglis, singling out Nathan Lyon’s dismissal of South African captain Temba Bavuma in the penultimate over of the day.

Bavuma had battled for almost three hours, scoring 35, before he tried to whip a ball from off-spinner Lyon through midwicket. The ball spun sharply and hit the stumps.

“I think we controlled the tempo really well in that last session,” said Inglis of a period in which South Africa scored only 87 runs in 34 overs.

“Although they were playing well, they weren’t really getting away from us. I thought Gaz [Lyon] bowled brilliantly and looked threatening the whole time.

“When you work for a couple of hours and get the rewards right at the end, it’s really satisfying,” said Inglis.

South African off-spinner Simon Harmer, who bowled 37 overs and took four for 104 in Australia’s second innings, said spin was playing an increasing role in the series-deciding contest between the world’s two leading Test teams.

“If you look at how the wicket changed from this morning to this evening, it’s been quite a dramatic change. I think Mitchell Starc does a pretty good job of churning up the wicket [with footmarks from his follow through as a left-arm bowler]. So yeah, I definitely think that spin is probably going to come into it a lot more than it has in the first two-and-a-half days.”

Harmer said the remaining South African batsmen could not afford to look too far ahead in terms of trying to post a total that would give them a chance.

Although Lyon had to wait until late in the day, he posed a significant threat as he sent down 14 overs, finishing with one for 31.

But it was fast bowlers Starc and Josh Hazlewood who made the initial inroads.

Starc, who took six for 72 in the first innings, again struck crucial blows, dismissing Aiden Markram and Marques Ackerman while Hazlewood claimed the wicket of David Bedingham, out hooking for the second time in the match.

Inglis earlier completed his second Test century, scoring 102 before Australia were bowled out for 429 after starting the day on 330 for four.

He told journalists that he only found out he was playing when Steve Smith ruled himself out with a neck injury on the morning of the match.