Age no barrier for supreme Serena

Williams remains in a class by herself as she claims Slam title No 20

Serena Williams has won Wimbledon five times and will be a hot favorite to make it six when the grass-court classic gets underway in three weeks time in London.

If she makes the punters happy by doing so she will, for the second time in her career, hold all four Grand Slam titles at the same time - and will stand halfway to becoming just the fourth woman to win all four in the same year.

It is a clear sign of how dominant the 33-year-old American has become in the women's game, 17 years after making her debut in Grand Slam tennis.

To date she has won 20 Grand Slam titles, just two shy of the Open era record of 22 held by Steffi Graf, and most worringly for her opponents, she seems to be accelerating.

Seven of those have come since she hooked up with French coach (and boyfriend) Patrick Mouratoglou in June 2012 after a stunning first-round upset at the hands of Virginie Razzano in the French Open - the first, and to date only time, she has gone out of a Grand Slam event at the first call.

At that time Williams had been beset with a succession of injuries and lack of motivation and she credits Mouratoglou with turning things around for her.

"Beforehand her career was full of ups and downs," he said after her three-sets win over Lucie Safarova in Saturday's French Open final.

"I had the impression that she lacked motivation at times and also she was very often carrying an injury."

Now, he says, she is perfectly capable of winning five Grand Slams in a row at Wimbledon and New York, although he cautions that it is still a big ask.

Helping Williams's cause - and worringly for women's tennis in general - the opposition is not exactly of the highest quality.

Part of the problem stems from the early retirements of Belgian pair Justine Henin and Kim Clijsters, both of whom were capable, at their best, of going head to head with Williams

Nowadays long-time foes and prematurely annointed successors Maria Sharapova, Ana Ivanovic and Caroline Wozniacki seem incapable of beating her, mid-twenties challengers Petra Kvitova and Victoria Azarenka have problems with the pressure that comes at the top and young guns such as Eugenie Bouchard and Sloane Stephens have taken backward steps this year.

That left a Paris tournament that had no player under the age of 25 in the semifinals.

The stage therefore looks set for Williams to continue her domination of women's tennis, at least for the next couple of years, as long as she stays healthy and motivated.

Then the debate can be engaged over who is the greatest female tennis player of all time - Maureen Connolly, Margaret Court, Martina Navratilova, Graf and Williams being the likeliest choices.

Navratilova, who presented the French Open trophy to Williams at Roland Garros on Saturday, believes the American is ideally placed.

"She has really dominated the sport in the last three years," the 18-time Grand Slam winner said. "What is impressive to me is that she's doing it at this age.

"It remains to be seen how deep she can go into the 20s (Grand Slams), depending on how her body holds up and on motivation. Even if she gets to 22, passing Margaret Court (24) is still a long way away.

"It definitely gets harder when you are in your 30s but at the same time, the new generation hasn't quite caught up to Serena so she has a nice window there."