Having impressively negated offspinner Nathan Lyon on a turning Newlands surface, Matthew Breetzke became the latest South Africa batter to meekly succumb to the short ball. But his was the only wicket to fall in a tense fourth morning of the series-deciding third Test as South Africa's lead grew to 102 runs. They scored just 62 runs for the session, but Ryan Rickelton held firm to defy Australia's push and he reached lunch on 39 not out.

Breetzke had batted with maturity in the session, shedding the horizontal bat shots given the slew of ham-fisted dismissals from South Africa batters through the match.

But he lost patience on 43, failing to execute a pull shot off Pat Cummins that was top-edged to fine-leg. It was Cummins' first wicket since the opening Test, ending a barren run of 374 balls since he had last struck.

Rickelton batted through the session, but had an anxious moment just before lunch when Australia appealed a catch at slip off the part-time spin of Matt Renshaw. An umpire's review, however, confirmed there was no outside edge.

The surface is still playing relatively placidly under the Cape Town sunshine, but Lyon is proving to be a handful as he targets the footmarks. Several of his deliveries have turned sharply off the footmarks and only narrowly missed the wickets.

South Africa resumed at 140 for 4 with a lead of 40 runs at the start of the day as they started their quest to build a big total and ensure Australia faced a challenging fourth-innings chase.

Cummins didn't waste any time and immediately deployed Lyon, riding high after clean bowling captain Temba Bavuma, late on day three. He encountered a more resolute effort, with Rickelton and Breetzke focused on survival.

It took almost 20 minutes into the day's play for the first boundary when Rickelton rocked on the back foot to punch Lyon through the covers. Runs were hard to come by against accurate bowling, with the tension heightening as Breetzke poked his tongue out at Starc amid a verbal exchange.

Only 31 runs were scored by the drinks break, but South Africa didn't mind even though they would have ideally hoped to shift through the gears before the second new ball.

Breetzke did well to thwart Lyon, carefully focusing on the sharp turn from the rough. He did have his heart in his mouth after a wicked delivery spun through his defence and only just missed hitting the off stump.

Having faced more than 100 balls, Breetzke felt more comfortable and hit a superb boundary through the covers off Cummins, who was still searching for an elusive wicket.

In a rare sight, Breetzke went after Lyon with a slog sweep that rocketed to the boundary as the partnership reached fifty. But Breetzke could not help himself and gifted a wicket to Cummins, who finally celebrated a wicket.

The pressure grew on southpaw Rickelton, who didn't have to quite agonise over the footmarks like the right-handed batters. He stroked Lyon for a sublime boundary down the ground to notch 1000 career Test runs and looms as a key for South Africa in what will be a pivotal second session.