Cape Town - Springbok coach Peter de Villiers has launched a scathing attack on Crusaders star Sonny Bill Williams, describing his flamboyant offloading style as "nonsense" and a poor example for young rugby players.

According to Rugby Heaven correspondent Marc Hinton, De Villiers's latest assault on the All Black Rugby World Cup certainty comes in an interview for a South African online website magazine. It follows comments he made previously to South African reporters suggesting the Crusaders No 12 would be found out when he had his space cut down.

Williams, though, was brilliant in the Crusaders' gritty 20-14 Super Rugby victory over the Stormers in Cape Town last Saturday, cutting the competition's best defence open with his offloads, ball-strips and power running.

"I hope he will mature his game," said De Villiers. "He's doing everything wrong what rugby principles require of you in the game.

"Backhand passes shouldn't be the norm... it has become the norm, now everyone wants to do that kind of nonsense.

"This kind of non-rugby stuff he's doing, if it comes off it's brilliant, but do you have control over these kind of things? If you get to the international level where people work you out, then you have to be in control of what you're doing."

De Villiers said a youngster watching Williams in Super Rugby would get the wrong impression of the core skills needed.

"He'll spend hours and hours on the things that are not important and never master the most important things of rugby."

Asked if he'd worked Williams out, De Villiers said: "If you close down his space, put pressure on him and hit him hard, and if you don't dance around with him like he does, then no way..."

De Villiers's comments should, of course, be taken in context. The Boks coach has long been renowned for verbalising his bizarre thoughts, and it just may be that he has identified Williams as a clear threat to his team's World Cup defence later this year.