Is it Kournik-over for loser Anna?

Tennis pin-up Anna Kournikova has been warned by sportswear giant adidas that she must be more successful if she wants to keep her lucrative sponsorship deal.

The 20-year-old Russian earns millions of pounds from her looks but has yet to claim a singles title.

Kournikova has failed to live up to expectations since she shot to fame by reaching the Wimbledon semifinals in 1997. She is now ranked No.66 in the world.

She banked less than £500,000 in prize money in 2000 yet earned almost £7million in deals with firms such as sports bra maker Berlei. But German sportswear maker adidas says Kournikova must start focusing more seriously on her game, rather than relying on her appearance for plaudits.

Chief executive Herbert Hainer said: "More sporting success is vital for her to be taken seriously as an athlete. She will have to train harder and then attack to hopefully win her first tournament."

Adidas also sponsors Kournikova's arch-rival and doubles partner Martina Hingis who, by contrast, has captured five Grand Slam singles titles. The 21-year-old Swiss claimed recently that Kournikova was envious of her success, despite her earnings. 'She would love to swap her wealth for my Grand Slam titles,' Hingis said.