Nine-times Wimbledon champion Martina Navratilova insists the players on the women's circuit "have to get better" if they are to challenge the dominance of the Williams sisters.

Serena Williams beat big sister Venus to win her first Wimbledon singles title, having already won the French Open earlier this year.

Asked how their peers could hope to match them, Navratilova told BBC's Wimbledon 2002 programme: "The others simply have to get better. The women will have to get in the gym, get on the track and be faster and stronger.

"You need someone who has the variety, someone who can get into the net as well as play at the baseline."

Fellow BBC analyst Pam Shriver added: "It's really important for the other players to answer with hard work, a good attitude and dedication.

"It's a little painful at the beginning but once the competition catches up it makes it more interesting."

However, Navratilova believes the Williams sisters are well capable of carving up Grand Slam titles between them for another decade.

"I think if they both stay committed they can do this for another 10 years, easy," she said.

"Right now they are dominating. They've been doing it all year.

"Lindsay Davenport matches up with power but not the speed, and Martina Hingis needs to get a better serve, she is losing too many points on her second serve.

"If Lindsay gets a little more mobile she can compete, but you have to have variety. You have to mix it up, try to make them wonder what you are doing out there."