It had been a tumultuous few days for South Africa skipper Faf du Plessis, who was found guilty of ball-tampering by the International Cricket Council after he was caught on camera sucking a mint and rubbing saliva into the ball during last week's second Test against Australia in Hobart.

Given all the drama from his much-publicised appearance at the hearing it was a remarkable effort of concentration and will for du Plessis to conquer the Australian bowlers and post his sixth Test century, one he rates as his best.

"My best. Everything. What was required to get to this point now. Surprisingly, technically, I was the best this whole series. I felt really good, but in the context of everything else, (it was) the best," he told reporters.

"I was really motivated. I felt it needed a character test, and the only way I could do it was by scoring runs."

But du Plessis, who was booed by the home crowd as he came out to bat with his team wobbling at 44 for three, was dismayed by yet more booing when he reached his courageous century off 147 balls.

"I was expecting a little bit of hostility, but not to that extent," he admitted.

"When I came out to bat I was obviously quite aware of it and as the innings went on it disappeared a bit.

"But to be really honest when I got to 100 I wasn't expecting to still get booed, so that was pretty disappointing."