The first Test had been overshadowed by the Warner-Quinton de Kock saga but all the talk in the second Test has centered around Rabada.
Losing Rabada, who hit the 151 km/h mark on Sunday and snared five wickets in 18 deliveries on Friday, would be a big blow to South Africa's hopes of their first home Test series win over Australia in the post-apartheid era.
The wicket brought Lungi Ngidi to the crease and either in a desperate attempt to get the No.11 on strike or simply out of ideas, Smith put eight fielders on the boundary to give de Villiers a single. It was his 22nd Test century and first since returning from his sabbatical.
"I needed to get away and not really know where I was going", he said.
It's not that he fell out of love with test cricket, de Villiers said, but rather fell out of love with the amount he was playing. I was just exhausted of playing. I was just flat, physically and mentally.
De Villiers made batting look outrageously easy but he insisted it was anything but, especially when he approached three figures.
The 22-year-old is one of the best bowlers in the world but his white line fever is cause for concern. "It seemed like he was batting on a different wicket to everyone else".
Australia's fast bowlers, who had a heavy workload on the previous day, wilted under an assault in which De Villiers played strokes that were sometimes breathtaking. He celebrated exuberantly when he reached the mark with an upper cut for four against Pat Cummins.
"It felt like 10 out of 10 to get my hundred, it was right up there with one of my best, and I was very nervous in the 90s".
Majestic AB, Rabada put Proteas in control
"I had to keep reminding myself in the 90s that it was not about myself, but about contributing to the team as much as possible".
In-form South Africa bowler Kagiso Rabada has again been reported for a send-off in the second Test with Australia.
Rabada roared out a few words into Warner's face and the reaction from the umpires at the time suggests he could also be charged with misconduct for that excessive celebration. They took a lead of 41 runs with wickets to spare at the close of the day.
Rabada was found guilty of a level two International Cricket Council (ICC) code of conduct offence of "inappropriate and deliberate physical contact with a player" after leaning with his shoulder into Australia captain Steve Smith when he dismissed him in the first innings, an ICC statement said.
De Villiers noted Rabada's antics were not entirely dissimilar to the emotion showed by compatriot Dale Steyn, who often celebrates wickets like a man possessed.
"Talking to de Villiers in the way we did I think it motivated him".
"Well it'll be handy for us not to have to face him, that's for sure", said Australia assistant coach David Saker.
Rabada, recently ranked the No. 1 bowler in test cricket, has also previously been disciplined three times for his actions after dismissing batsmen and served a one-test ban in England previous year.