SYDNEY: Former junior Australian Open champion Brydan Klein said Friday he is on his final warning as he serves out a suspension for making a racial slur against an opponent.

Klein, 19, was handed a six-month ban, in force from July 20, by the Association of Tennis Professionals (ATP) and fined 10,000 US dollars for calling black South African Raven Klaasen a "kaffir" during the Eastbourne International in England in June.

As part of his punishment Klein was required to undergo a racial sensitivity course, which is likely to reduce his ban to four months, enabling him to return to competitive tennis by mid-November.

Klein has a history of clashes with sporting officialdom, having been suspended from the Australian Institute of Sport for repeated on-court misbehaviour.

The tennis bad boy says he cannot afford to slip up again.

"I'm definitely on my last warning," said Klein, speaking about the incident involving Klaasen.

"This has been a step back for me and it hasn't been a nice experience."

Klein, ranked 223 in the world, said he had thought long and hard about what happened and had apologised to Klaasen.

"I've went over everything that happened and reflected and refreshed my mind," Klein told reporters.

"I'm going to seek more advice over these four months.

"It's like a red mist, it happens and straight after you regret it.

"Straight after it I called my opponent and apologised. He said he accepted my apology."

Klein said he will be using the time ahead of his comeback to get himself in the best possible shape ahead of the Australian summer of tennis.

"I'm using this four months to my advantage," he said.

"I'm going to try to work really hard on my mental side, and obviously my tennis, my physical side."