Stumps Australia 147 for 2 (Labuschagne 79, Khawaja 54*, Nortje 2-26) vs South Africa

Marnus Labuschagne and Usman Khawaja hit half-centuries for Australia on a truncated day one before Anrich Nortje helped South Africa claw back into the third Test at a gloomy SCG.

After captain Pat Cummins won a crucial toss and elected to bat on a dry surface, Australia reached stumps at 147 for 2 with Khawaja unbeaten on 54 and Steven Smith yet to face a delivery.

Labuschagne fell for 79 on what turned out to be the final delivery of the day's play. Only 47 overs were bowled due to bad light and rain much to the disappointment of the 31,000 crowd in another Sydney Test match affected by inclement conditions.

Labuschagne and Khawaja had built a strong platform with a 135-run partnership after the early loss of opener David Warner for 10. There was a delay of more than two hours due to bad light before five overs were squeezed in late in the day and Nortje capitalised with a cracking delivery to remove Labuschagne.

Exerting plenty of energy, Nortje conjured sharp bounce and pace on the slow surface to produce an unplayable delivery that had Labuschagne caught behind.

After a lionhearted effort in Melbourne, Nortje was again the standout with 2 for 26 from 11 overs having earlier taken the wicket of Warner. He has kept a struggling South Africa buoyant after Australia threatened to grab an early stranglehold of the contest.

Labuschagne had been irrepressible until on 70 he appeared to be dismissed out of nowhere when he edged seamer Marco Jansen to first slip where Simon Harmer claimed a low catch.

It was given out on the soft signal but Labuschagne stood his ground and it seemed difficult to prove from replays whether Harmer had his hands under the ball close to the turf.

Third umpire Richard Kettleborough overturned the decision much to the frustration of South Africa. It only furthered Labuschagne's reputation as a rather charmed batter but he had played imperiously before that contentious incident with five boundaries in 12 balls to go from 40 to 61.

After bowling well before lunch, Harmer trapped Khawaja lbw with the second delivery of the second session only for the decision to be reversed when replays showed the ball hit the glove first.

Having revived his career a year ago with twin centuries against England on this ground, Khawaja passed 4000 career Test runs en route to a half-century.

Under-pressure South Africa captain Dean Elgar once again made questionable decisions, including under-utilising Harmer who bowled just five overs even though his off-spin particularly threatened left-handed Khawaja.

Elgar, however, backed underperforming left-arm spinner Keshav Maharaj who bowled nine overs for 35 runs with Labuschagne and Khawaja sweeping effectively against him.

Maharaj has now bowled 52.5 overs without reward in this series.

While Nortje toiled, spearhead Kagiso Rabada continued his underwhelming series to finish with 0 for 45 off 12 overs. He unsuccessfully reverted to bowling short against Labuschagne, who counterattacked with ease.

Ashton Agar, Josh Hazlewood and Matt Renshaw were named in an Australia team attempting a clean sweep of the series and a spot in the World Test Championship final in June.

There was drama when Renshaw, playing his first Test since 2018, tested positive for Covid-19 on a rapid antigen test after feeling unwell before the day's play, but he will continue to play in the match.

With the SCG surface set to play more traditionally, Australia named two frontline spinners at home for the first time in six years with left-arm spinner Agar making his return having not played Tests since 2017.

Regular quick Hazlewood returned from a side strain having edged out Scott Boland and uncapped tearaway Lance Morris.

Along with Harmer, who replaced Lungi Ngidi, South Africa named batter Heinrich Klaasen in place of Theunis de Bruyn who returned home for the birth of his first child.

South Africa still have a slim chance at qualifying for the WTC final with a consolation victory as their spirit lifted after Njorte's late heroics.