Lunch South Africa 244 for 7 (Maharaj 49*, Harmer 45*, Cummins 3-53, Hazlewood 2-45) trail Australia 475 for 4 dec by 231 runs

Simon Harmer and Keshav Maharaj combined for an outstanding partnership as South Africa mustered belated fight on day five to thwart Australia's push for an improbable third Test victory at a sunny SCG.

At lunch, South Africa needed 32 runs to avoid the follow-on target with Maharaj and Harmer nearing half-centuries, their partnership an unbroken 72 for the eighth wicket. A minimum of 58 overs are left, but a draw is increasingly looking likely even though there is only a small chance of rain forecast in Sydney for the rest of the day.

Amid blue skies and warm conditions, the pitch has played well and not deteriorated as expected after Australia quicks Pat Cummins and Josh Hazlewood conjured inconsistent bounce late on day four.

Part-time spinner Travis Head was the most dangerous bowler in the first session of day five, and claimed its only wicket by removing Marco Jansen for 11 off 78 balls.

But Australia were left largely frustrated in their bid for a series sweep to book a spot in the World Test Championship final in June.

Given their batting frailties, South Africa faced an uphill battle against a fired-up Australia attack. They had not drawn a Test in their last 43 matches dating back to 2017.

South Africa started precariously placed at 149 for 6 after Cummins and Hazlewood bowled superbly late on day four under fading light.

But Jansen and Harmer batted cautiously to defy Cummins and spinner Nathan Lyon in a stonewall. Harmer scored the first runs of the day's play off its 20th delivery, and shortly after impressively pulled Cummins to the boundary.

Jansen didn't score until the 32nd ball he faced for the day, underlining his determination to play a rearguard. He did occasionally nervously prod at Lyon, including a close shave when an inside edge fell via his pad short of Steven Smith at slip

Lyon, who has a modest record at the SCG, started from the get go and targeted the footmarks outside off stump. He initially struggled with his accuracy before finding his radar but couldn't find the breakthrough.

Just before the second new ball, Cummins turned to Head, who justified the faith by dislodging Jansen caught behind with a delivery outside off stump that stayed low.

Head continued to probe but chances were missed including a sharp return catch to reprieve Maharaj.

Cummins had no hesitation in taking the second new ball and Hazlewood immediately conjured nasty bounce much like he had done the previous evening.

But runs also flowed in South Africa's desperate attempt to pass the follow-on target with Maharaj counterattacking Cummins with several belligerent pull shots to the boundary.

After rarely being used in his first Test match since 2017, spinner Ashton Agar came into the attack an hour into the day's play. But he mostly failed to threaten with Australia's frontline spinners upstaged by Head.

Showcasing belated grit and defiance, South Africa are poised to end a dire series defeat on a positive note.