Boxing trainer Peter Smith is upset with colleague Colin Nathan, whom he accused of claiming undeserved credit for laying the foundation for former jockey Kevin "Two Guns" Lerena to become one of the most revered boxers in SA.

Lerena, who has no amateur experience, has held the SA, WBF Africa, WBC Youth and WBA Pan African cruiserweight belts.

The 26-year-old left-hander is now the IBO holder and is rated No 11 by the WBA and the IBF, and eighth by the Ring Magazine.

Smith's anger emanated from a Sowetan report on Monday, a day after Lerena stopped highly rated Artur Mann, the Kazakhstani, in the fourth round at Emperors Palace.

Sowetan called Nathan to find out who were the first trainers to work on Lerena. Nathan said he trained the boxer first before he joined Peter Smith.

"Kevin started his boxing at Hotbox when he was 14 years old," said Nathan, who owns that gym.

But Lerena dismissed that as hogwash. "I used to train at his gym as a client, not as a boxer and he never trained me. I was trained by Vusi [Mtolo] before I joined Peter Smith," said Lerena.

Smith said: "I find it very disrespectful for Colin to say that. It is actually defaming my character."

Smith said it was his then boxer Chris van Heerden who advised Lerena to join him.

"I trained Kevin and we won five straight fights with KOs," said the former heavyweight pro boxer. "Kevin was then advised to join Colin and he left me. They had one fight together and Kevin came back and asked me to take him back. I refused and advised him to join my brother [Sean]."

Sean and Lerena did well together until the boxer lost to Johnny Muller - his only defeat - in 2014.

"Kevin then approached me again and asked if I could take him back otherwise he would retire from boxing," explained Peter. "I spoke to my brother and Kevin and we all agreed that he rejoins me. I was told that I was wasting my time because Kevin was not going anywhere."

Smith took that as a challenge.

"We work well together; he understands me and my teachings. We had a rematch with Johnny and we stopped him," he said.