"My fire to play for the Proteas was slowly smothered," admits the former captain due to his relationship with head coach Mark Boucher, which led to his Test retirement
Faf du Plessis says South Africa believed Australia were ball-tampering before the controversial episode at Cape Town in 2018.
The third Test was dominated by the Sandpapergate scandal, leading to Cameron Bancroft being slapped with a nine-month ban, while David Warner and then captain Steve Smith were handed 12-month suspensions.
Du Plessis' side had been alerted to a possible infringement prior to the episode that unfolded on the third day at Newlands. The manner of Australia's victory in the first Test by 118 runs in Durban alerted the team to a problem before the series moved to Port Elizabeth.
"During the first Test in Durban, the Australian pace attack had got the ball to reverse insanely," Du Plessis wrote in his autobiography ‘Faf: Through Fire’.
"Mitchell Starc claimed nine wickets and, although I regard him as one of the best proponents of reverse-swing bowling I have ever seen or faced, those deliveries in Durban were borderline unplayable.
Australia's Cameron Bancroft, Steve Smith and David Warner were reprimanded (Ashley Vlotman/Gallo Images/Getty Images)
"He would come in around the wicket with a badly deteriorated ball and get it to hoop past us. Our balls had also reversed but not nearly as much as theirs.
"We suspected that someone had been nurturing the ball too much to get it to reverse so wildly, and we watched the second Test at St George’s through binoculars, so that we could follow the ball more closely while Australia was fielding.
"When we noticed that the ball was going to David Warner quite often, our changing room must have looked like a birdwatching hide as we peered intently through our binoculars.
"There was a visible difference between how Mitchell Starc got the ball to reverse in the first Test in Durban and the final Test in Johannesburg. We now know that there was an obvious reason for that."
Du Plessis adds that Smith, whose punishment included a two-year ban from leadership positions, didn't do "much wrong".
Faf du Plessis' South Africa careerBATTINGTESTMatches: 69; Runs: 4,163; Highest score: 199; Average: 40.02; Centuries: 10; Fifties: 21ODIMatches: 143; Runs: 5,507; Highest score: 185; Average: 47.47; Centuries: 12; Fifties: 35T20IMatches: 50; Runs: 1,528; Highest score: 119; Average: 35.53; Centuries: 1; Fifties: 10AS CAPTAINTEST (2016-2020)Matches: 36; Won 18; Lost: 15; Drawn: 3ODI (2013-2019)Matches: 39; Won 28; Lost: 10; No result: 1T20I (2012-2019)Matches: 37; Won 23; Lost: 13; Tied: 1
The 38-year-old has previously been found guilty of ball-tampering by the ICC following an incident in 2016 against Australia but avoided suspension after being found to use a mint to alter the condition of the ball.
It was a blot on Du Plessis' copybook during a South Africa career that included 69 Tests, 143 one-day internationals and 50 T20Is.
He accuses head coach Mark Boucher and CSA director of cricket Graeme Smith of a lack of support, pushing him into Test retirement last year.
Incidents included when he said the team "did not see colour" after Temba Bavuma was dropped during the England Test series, his removal as white-ball skipper and being undermined in the decision-making process over when to deploy a nightwatcher.
"At the end of the Test series against England, I questioned whether my flame still burned as brightly as before," he added.
Du Plessis has outlined the breakdown of his relationship with Boucher (Sydney Seshibedi/Gallo Images)
"My desire to lead and my fire to play for the Proteas was slowly smothered. Mark and I didn’t click either.
"I began to understand that it would be better for the team to have a new captain, rather than someone who could not connect with the coach."
Du Plessis claims he tried to organise a meeting to inform Boucher of his decision, but the request fell on deaf ears.
"His silence confirmed to me that the decision to retire from Test cricket was the right one," he wrote.
"What really brought it home to me was that even my biggest opponent, David Warner sent me a kind message to congratulate me on my Test career."