Brad Haddin believes AB de Villiers was the difference between defeat and victory in the second Test, with Australia desperate to curtail the South African superstar's hot form.
Kagiso Rabada earned man-of-the-match honours in Port Elizabeth, snaring a haul of 11-150 then being slapped with a two-Test ban that the Proteas have appealed.
However, de Villiers was arguably even more important in the Proteas' series-levelling victory.
The gifted batsman finished 126 not out in South Africa's first innings, steadying with an array of flashy strokes after a post-tea collapse of 4-28 on day two.
"He's as good as I've played against," Australia's fielding coach and former keeper Haddin said.
"Everyone was fighting and batting OK but he showed a different class out there in that game. It just changed the whole momentum of the game.
"If we had have got him there early we would have been talking about a different result. That's how big an innings that was."
De Villiers, the leading run-scorer of the series, also scored an unbeaten 71 during the first Test in Durban.
Mitchell Starc has already made it clear that de Villiers will be Australia's No.1 target when the series continues in Cape Town on Thursday.
"We feel we're pretty comfortable against the rest of their batting line-up. I think we showed in the first Test how quickly we can go through them," Starc said.
"He was a mainstay in the first innings of that first Test and again in the second Test, so they rely heavily on him.
"He's been the linchpin for them and we've spoken about some good plans for him.
"You've got to think outside the box a lot more with him."
Meanwhile, Haddin has also been impressed with how clean Quinton de Kock's glovework has been while keeping up to the stumps to Vernon Philander during the four-Test series.
"He's been faultless up there and he's had to take a lot of balls up to the stumps, Haddin said.
"There is not as much feet movement or the elegance of an Ian Healy, but he just catches everything, he's just such a natural catcher."
