After a Wimbledon tournament full of shocks, Martina Navratilova said it was time the top women players "stepped up to the plate" following the shock retirement of world number one Justine Henin.
Navratilova, nine times champion at Wimbledon, said: "It is a changing of the guard. It is the first time ever we don't have one of the top four seeds in the quarters."
The tournament lost much of its glamour when Ana Ivanovic and Maria Sharapova were knocked out in early rounds and Jelena Jankovic and Svetlana Kuznetsova followed suit.
Now the prospect is looming of sisters Venus and Serena Williams heading for their third Wimbledon final against each other. The pair have dominated 21st century Wimbledon, winning six singles titles between them.
Navratilova told Reuters: "Nobody has stepped up to the plate. Maybe this will be the resurrection of Serena and Venus. Maybe they will end up number one and two at the end of the year."
"We have the new generation, a lot of new players coming through in their late teens and early 20s. The middle is much stronger, the top is a little bit weaker," she said.
The world of tennis was shocked in May by the surprise announcement from Henin that she was to retire from the game at the pinnacle of her powers.
Navratilova, noting how the landscape of the women's game has changed so suddenly, said "It is too even at the top and nobody has risen to the top."
She argued that what tennis fans wanted were champions like Roger Federer and Rafael Nadal slugging it out in Grand Slam finals.
Reflecting on her own titanic struggles against Chris Evert, she said "In the old days people were complaining that it was always Chris and Martina in the finals but the bottom line was they wanted to see Chris and Martina in the finals."
The WTA, ruling body of the women's game, has recognised the danger of burnout, cutting the number of top tier tournaments next year from 25 to 20.
But Navratilova, appearing at Wimbledon as a TV commentator, complained that the tennis calendar was still too crowded.
"You are still going to end up playing 16 to 18 tournaments. The difficult part is playing on hard courts around the world. There is so much more travel than there used to be."
