Going for back-to-back WTC titles, Australia enter the decider as hot favourites after crushing the Proteas the last time the teams met back in 2022-23.
Labuschagne, who was once described as having "opening-itis", won the battle to be Usman Khawaja's fifth opening partner in 18 months over teenager Sam Konstas.
Josh Hazlewood returns to partner fellow star quicks Pat Cummins and Mitchell Starc in his first Test since December.
Cummins described Australia's preparation as "unreal".
All the guys in the team are ready to go," he said.
"Everyone's come together and we have had about 10 days of preparation.Â
"I don't think there's any extra pressure. We've been here before and won it."
South Africa, who won seven-straight Tests to qualify for the final, are attempting to break a title drought in ICC tournaments dating back to 1998.
"The more finals you play in, you obviously improve your chances of winning. It doesn't weigh heavy on us," South Africa coach Shukri Conrad said.
"It's unfair to burden this group with anything that's gone before.
"We know we want to and we need to win another ICC event, but whatever tags come along, we don't wear that."
AUSTRALIA: Usman Khawaja, Marnus Labuschagne, Cameron Green, Steve Smith, Travis Head, Beau Webster, Alex Carey (wk), Pat Cummins (capt), Mitchell Starc, Nathan Lyon, Josh Hazlewood.
SOUTH AFRICA: Aiden Markram, Ryan Rickelton, Wiaan Mulder, Temba Bavuma (capt), Tristan Stubbs, David Bedingham, Kyle Verreynne (wk), Marco Jansen, Kagiso Rabada, Keshav Maharaj, Lungi Ngidi.
This AAP article was made possible by support from Amazon Prime Video, which is broadcasting the World Test Championship final.
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