Australian tennis ace Thanasi Kokkinakis faced court action Thursday from cereal giant Kellogg, which is not happy at plans to use his nickname "Special K" commercially.

Kokkinakis and doubles partner Nick Kyrgios have been dubbed the Special Ks by media and the public, and the 21-year-old wants to use the moniker as a branding campaign across clothing and tennis wear.

But the US-based multinational — which has held an Australian trademark for its Special K breakfast cereal for more than 50 years -- launched court action to stop him.

A spokeswoman for Kellogg told AFP that the Kokkinakis family had tried to register their own trademark, which sparked the retaliatory action, with a procedural hearing on Thursday.

"Kellogg will continue to defend our very strong and iconic Special K brand -– which is known and loved by many Australians," the company said.

The Sydney Daily Telegraph said Kokkinakis, who has slipped down the rankings from a career-high 69 due to injury, wanted to create a logo and brand for himself in a similar way that Roger Federer and Rafael Nadal have created lucrative businesses marketing their own range of products.

It is not the first time an Australian player has become embroiled in a trademark dispute, with Lleyton Hewitt losing a case in 2011 over the use of the term "C'mon", which was a hallmark of his game.

Another Australian had already trademarked the phrase in 2004, the newspaper said.

Source: AFP