Cummins backs Australia's new-look top three; Bavuma smells an 'opportunity' there

South Africa see a potential vulnerability in Australia's top order with Marnus Labuschagne asked to open for the first time in Test cricket, as part of a reshuffle that sees Cameron Green return in a new position at No. 3. But captain Pat Cummins has backed big-match temperament to shine through.

Australia's key selection debates fell the way they were expected to for the World Test Championship final, with Labuschagne retained ahead of Sam Konstas and moved up to accommodate Green, while Josh Hazlewood returned to the pace line-up after injury.

It was the identity of Usman Khawaja's opening partner that had generated most interest ahead of the match with the selectors ultimately backing Labuschagne's experience and overall record against a strong South Africa attack despite averaging 28.33 in this WTC cycle. Konstas, who sparkled on debut against India with an audacious 60 off 65 balls, has two centuries in a 17-match first-class career so far.

"Cam Green, the last few weeks he's had, coming back in great form, we thought he deserved a spot in the batting line-up," Cummins said ahead of the match. "We thought three probably suits him best. And then, with Marnus, we thought it's one spot up really. It's not too different to batting three. He's done well here in England in the past.

"I think our selectors are probably showing that they're happy to give someone an extra little run rather than pull the pin too early. He's played some crucial knocks in getting us here. Look back at the MCG [against India], his batting was right up there as a difference in that match. I think it's part rewarding those guys that have got us here."

The reshaped top order will be tasked with laying the foundations against Kagiso Rabada, Marco Jansen and Lungi Ngidi, with the latter having won a tight selection race ahead of Dane Paterson.

"I think there is an opportunity there," South Africa captain Temba Bavuma said when asked about Australia's opening situation. "I think the conditions as well, I believe, bring us into the game a lot. With the swinging ball, [it's] very different to Australian conditions. Different to South African conditions as well. So that definitely gives us an opportunity.

"I think both teams have formidable bowling attacks. I think the real opportunity is within the two batting line-ups and how they are able to kind of front up and give their bowlers a score to bowl at."

Labuschagne becomes Khawaja's fifth opening partner in the last 12 Tests. Head coach Andrew McDonald has previously said he would like a settled combination by the Ashes later this year and, while Cummins reiterated the latest decision was made with the singular focus on this Test, it looms as a vital moment in Labuschagne's career. He has been urged to be "busy" at the crease with his strike rate having come under scrutiny in recent series.

"I think the extra layer to that is, I do believe the wickets in Australia have been as hard as they've ever been, probably, in Test cricket for the top order," Cummins said. "But I think it's similar conversations to Davey Warner over here. I think it's more about the style and how they go about it.

"We love when they're busy and they're putting pressure back on the bowlers and that's our message here to Marnus. Opening the batting can be tough, but it can also be sometimes the best time to bat here before the Dukes ball actually starts swinging. There's runs to be scored there, so just keeping that positive intent I think is when he's batting his best."

As alluded to by Bavuma, it will be a tough assignment for South Africa's top order as well, which includes a makeshift No. 3 in allrounder Wiaan Mulder, who has only done the job twice previously, although Cummins was aware that some of those his team had not faced before had the potential to be dangerous.

"There's a few more unknowns going into the Test match which is exciting," Cummins said. "I think we're going to have to problem-solve on our feet a bit more. Their bowlers we have seen a little bit of, and there's a couple of big wicket-takers there. Rabada and [Keshav] Maharaj have been around for a fair while now and been successful. They're an obvious threat, but some of those younger or newer guys in the team that we haven't seen before, we're going to have to be pretty sharp on."

With the retention of Labuschagne, it means only Beau Webster has not played in an ICC final although he proved to be far from overawed on Test debut against India with a crucial contribution in the game that assured Australia their spot in the final.

"With some success you just want to experience more of it and that means when the going gets tough or the pressure is on you embrace that. You take it on," Cummins said. "You want to be the match winner. Hopefully you don't get overwhelmed by big moments.

"That's been most of the conversation this week. The guys just have excitement. They want to get out there. They want to play well. They want to win. There's no fear of failure or if it doesn't pan out."