BONGANI "the Cyclone" Mwelase fired a broadside at Lovemore Ndou after the Australia-based veteran verbally attacked him ahead of their September 18 dual.
Ndou will defend his IBO welterweight belt against Mwelase at Emperors Palace.
Ndou said though Mwelase could be a good fighter, he would never realise his potential because he lacks discipline.
Mwelase was livid after reading Ndou's threatening comments in Sowetan yesterday. The 27-year-old Mwelase maintained that his potent mix of power and poise would be hard to beat on September 18.
The eloquent WBF junior middleweight holder said: "Lovemore is a washed-out fighter and an old-timer who lacks the skill.
"At 38 he is heading for an unplanned retirement. I'm going to knock him down. Our fight will not be a David versus Goliath affair but a simple suicide for Lovemore."
Mwelase, the former SA, WBC International and WBF welterweight champion, said Ndou had fought and lost to some boxers he thought were the best.
"That made him think he is also the best," said the left-handed Sowetan, who is trained by Johnny du Plooy.
Ndou has massive experience, which he gained from 60 fights, with 47 wins (31 KOs), 11 losses and two draws.
"I am not threatened by his fight record," said Mwelase, the 2006 Commonwealth Games gold medallist who has set the boxing scene alight since he turned professional in July 2006.
"This will be another knockout," he said.
He has stopped 12 of his 14 victims. "The IBO belt will be my perfect birthday present. I turn 28 on August 23."