MELBOURNE, DECEMBER 27

Facing pressure to retain his place in Australia's team, David Warner defied his critics and heatwave conditions with a spectacular return to form, scoring a memorable 200 in his 100th test.

Leading the three-match series one-nil, Australia had resumed at Melbourne Cricket Ground on Tuesday at 45-1 in sunny conditions in reply to South Africa's lacklustre first-innings total of 189.

By stumps, Australia was 386-3, an overall lead of 197, with Alex Carey not out on nine and Travis Head unbeaten on 48.

While Australia is in a strong position, two of the home side's pace bowlers, Mitchell Starc and first-innings hero Cameron Green, are nursing finger injuries ahead of South Africa's second innings.

Steve Smith (85) and Warner (200 retired hurt) shared an entertaining third-wicket partnership of 239 runs, as Australia took control of the match in stifling conditions. Smith's exit at 314-3 was followed by Warner's dramatic departure 15 runs later, retired hurt due to cramp, with the crowd of 42,614 on their feet.

England's Joe Root is the only other player in test history to score a double century in his 100th test.

"It was an amazing knock and nice to be up the other end for a large chunk of it," Smith said. "The more he started to cramp, the more shots he started to play.

"It was energy-sapping. It was a tough day in terms of the heat. It was a pretty strange finish to the day. Boys were cramping left, right and centre."

Ever the showman, Warner tried to shrug off leg cramps, leaping in the air to celebrate his 200, before immediately buckling at the knees.

Unable to continue after crunching 16 fours and two sixes in his 254-ball knock in 99-degree Fahrenheit heat, Warner limped off with medical staff assisting him. The 36-year-old opener took the last few steps unassisted before crashing to the turf as soon as he crossed the boundary rope, looking elated and exhausted.

Asked if Warner should play on at test level, Smith said: "I don't see any reason why he can't continue playing."

The feisty left-hander scored his 25th test century and first since January 2020 off 144 deliveries, pulling a short ball to the leg-side boundary before launching into extravagant celebrations in the post-lunch session Tuesday.

Warner leapt into the air, waved his bat and blew a kiss to wife Candice in the crowd.

By tea, Australia held a 42-run advantage at 231-2.

Anrich Nortje finally ended the third-wicket partnership by removing Smith caught at gully at 315-3. The big fast bowler had narrowly escaped serious injury earlier in the day when an overhead "Spidercam" camera whizzed past and collided with his left shoulder and elbow, knocking the fielder to the turf in a bizarre incident.

"I didn't know what hit me," Nortje said. "I don't think it should be travelling at head height.

"The elbow's a bit sore, but otherwise it seems to be okay. I'll just monitor it and see how it goes with the doc."

Green was sent for a scan after retiring hurt for six at 363-3. The right-hander was struck by Nortje on the index finger of his bowling hand.

South Africa's bowling attack was also unable to complete the day as a unit, with pace bowler Lungi Ngidi leaving the field after breaking down with cramp following the first delivery of his 16th over.

Earlier, Warner was involved in a mix-up with Marnus Labuschagne who was run out for 14 at 75-2, two deliveries after Nortje had struck Warner on the helmet.

Smith and Warner guided Australia to lunch at 136-2, with Warner on 86.

Warner's day of celebration also included overtaking Justin Langer (7,696) and Mark Waugh (8,029) Tuesday to become Australia's seventh-highest test scorer.

Invited to bat first on Monday, the highlight of South Africa's 189 was a 112-run stand between Kyle Verreynne (52) and tailender Marco Jansen (59) for the sixth wicket. Australia's all-rounder Green claimed a career-best 5-27.

Nortje said South Africa was aware that Australia may have to use "maybe a back-up bowler" in its second innings if Green and Starc were unable to bowl.

"That's going to be a crucial stage for us," Nortje said. "Hopefully we can have a lot of batters in hand and work through the difficult stages with our top order and then try and cash in a little bit later on."