Come rain or sunshine, Ruann "Giant King" Visser will reign supreme against Justice "Venda Viper" Siliga when the two boxers exchange leather in a heavyweight bout at Sun Arena in Pretoria on Sunday, said veteran Cape Town boxing trainer Steve Kalakoda.

Kalakoda, who has trained a number of boxers including Nigerian Franklin Egobi - Lennox Lewis's chief sparring partner for his fight against Hasim Rahman in Brakpan in 2001 - has been tasked with the refinement of Visser's skills.

Visser's first defence against mandatory challenger Siliga, who is trained by Alan Toweel Junior, will headline 5th Elements bill.

"When I received a call from Ruann to help him with coaching, it was a very easy decision to make," explained Kalakoda.

"I knew that Ruann had the commitment, the heart and that he's a clean-living Christian. Once a young man has those capabilities, they will be successful.

"Ruann has all the attributes to be a champion or to reach the ultimate of his boxing potential. All he needed was someone to guide him along the way."

Added Kalakoda: "Once we started our first training I realised that he is a natural athlete. The last couple of years, his fighting was negative. He was going back, allowing smaller fighters to bring the fights to him.

"The natural instincts of South Africans, because of our rugby background, is aggression and attack.

"Ruann is a former rugby player, so it was not difficult for me to change and bring the natural aggression that he has in his rugby."

Kalakoda's first assignment was when Visser blasted Madars Trivols in round one in Germany on April 27.

"He went into the fight confident. When the bell rang, he went straight at his opponent, he knew exactly what he wanted to do; use his jab and strong right-hand combination," Kalakoda added.