Newlands likely not a one-off: du Plessis

In the wake of the revelation that Australia used sandpaper to alter the condition of the ball to generate reverse swing in the third Test in Cape Town, Proteas captain Faf du Plessis said he suspected the tourists had used similar methods earlier in the series.

Three players – Steve Smith, David Warner and Cameron Bancroft – have been sent home and suspended for their involvement in the ball-tampering scandal that has thrown Australian cricket into turmoil.

Smith, who has been banned for 12 months and stripped of the national captaincy for at least two years, has said Saturday's incident was the first time under his leadership his side had tried any artificial method of scuffing up the ball.

The aim of the unethical exercise was to accelerate reverse swing, whereby the ball swings considerably – and late – away from the rough the side of the ball, a craft that has at times had devastating effects through the three Tests of the series to date.

Depending on the abrasiveness of the pitch and the surrounding wicket square, reverse swing can take effect as early as 20 overs or sometimes not at all, but in South African conditions, the ball traditionally goes 'Irish' from around the 50-over mark.

It was when the Australians found reverse swing much earlier than expected that the Proteas and captain du Plessis suspected the visitors were somehow changing the condition of the ball outside of the usual means of bounced throws into the wicket or wicket square.

"I thought so, yes," du Plessis said when asked if he suspected the Australians had been nefariously roughing up the ball prior to the third Test.

"The series the ball has been reversing quite a bit.

"I joked about it this last Test match, (saying) I've never seen so many guys put up their hand to open the batting.

"Normally, it's green wickets and spicy (conditions) in the beginning (which concern batsmen) but now the biggest challenge in this series is coming in when the ball is tailing around.

"Whether that's at 30 overs or 50 overs. It was just the nature of when the ball was reversing (that made him suspicious), that's all.

Du Plessis added: "Without having any evidence of it, we thought there's no way that the ball can go so early.

"It's just unheard of for a South African series where the ball is (reverse-swinging) this much.

"We try and do the same, we try and get that ball to talk as much as possible. But we certainly don't walk around with sandpaper in our pockets."

While the Australians have been caught out for using a foreign agent to generate reverse swing, du Plessis – who has twice previously been charged with ball-tampering – said his side will not stop using the traditional methods, which can be stopped by the umpires if not carried out subtly, in the fourth and final Test in Johannesburg.

"To an extent it is a skill to try and get that ball to talk as quickly as possible because a ball going straight versus a ball going late and the other way is obviously a lot harder (to face)," he said.

"From the next five days' play point of view, we're not going to stop trying to do that.

"We're going to keep trying to get the ball to reverse with what is allowed."

Qantas tour of South Africa

South Africa squad: Faf du Plessis (c), Hashim Amla, Temba Bavuma, Theunis de Bruyn, Dean Elgar, Heinrich Klaasen, Quinton de Kock, Keshav Maharaj, Aiden Markram, Morne Morkel, Chris Morris, Wiaan Mulder, Lungi Ngidi, Duanne Olivier, Vernon Philander, Kagiso Rabada, AB de Villiers.

Australia squad: Joe Burns, Pat Cummins, Peter Handscomb, Josh Hazlewood, Jon Holland, Usman Khawaja, Nathan Lyon, Mitchell Marsh, Shaun Marsh, Glenn Maxwell, Tim Paine, Matt Renshaw, Jhye Richardson, Chadd Sayers, Mitchell Starc.

Warm-up match: Australia beat South Africa A by five wickets. Report, highlights

First Test Australia won by 118 runs. Scorecard

Second Test South Africa won by six wickets. Scorecard

Third Test South Africa won by 322 runs. Scorecard

Fourth Test Wanderers, Johannesburg, March 30-April 3. Live coverage