Du Plessis on the edge after copping fine

South Africa captain Faf du Plessis is just one minor over-rate offence away from copping a suspension for their upcoming Test series against Australia.

Du Plessis and his Proteas teammates were ruled to be two overs short in the second Test against India in Centurion, with du Plessis fined 40 per cent of his match fee and his teammates fined 20 per cent.

It also means there is now a strike against the skipper's name and if he's found guilty of another minor over-rate offence in the next 12 months in Test cricket, he will face a suspension.

For example, another over-rate offence in the third Test against India next week would likely mean du Plessis will miss the first Test against Australia in Durban, which starts on March 1.

An offence in the first, second or third Tests against Australia would lead to a ban for the subsequent match.

The Proteas fielded a destructive four-man pace attack in Centurion alongside spinner Keshav Maharaj, with their pace-heavy line-up likely to have contributed to the hosts being short of their over rate.

The pace quartet of Kagiso Rabada, Morne Morkel, Vernon Philander and Lungi Ngidi bowled 116.3 overs between them, with Maharaj bowling just 26.

The punishment came after the Proteas secured a series-clinching win in Centurion, which followed their victory in the first Test in Cape Town.

"The last five days took a lot of hard work," Du Plessis said. "The previous game at Newlands (where South Africa won by 72 runs) was almost on fast forward.

"This was completely different. It was a game of grinding, hard work and pushing ourselves for longer and longer.

"I take a lot of pleasure in winning games like this where the team needs a lot of heart, character and fight to get across the line."

Du Plessis made it clear he was going for a clean sweep in the third Test and would resist temptation to give fringe players an opportunity with the series already won.

"I favour being ruthless," he said. "You don't get many opportunities to beat big teams 3-0. For me it's about putting your foot on the gas."

The South African captain said that although his team had prevailed on an unusually slow Centurion pitch, he was unhappy about the conditions.

"We don't want something ridiculous but we want pitches with pace and bounce. We are not getting it right and it is not the first time it has happened, so I will be taking it up."