Left in her sister's wake, is this the beginning of the end for Venus?

Venus is waning. On the very day her sister Serena was receiving the WTA Tour 2002 player of the year award after winning three grand slams in a row, the elder Williams was suffering her worst defeat for 13 months, a 7-6, 6-1 drubbing from her fellow American Meghann Shaughnessy in the last 16 of the Nasdaq-100 Open.

The two moments may be connected. Venus's sober persona after losing to an opponent ranked outside the top 20 made a stark contrast with the smile depicted nearby on the toothpaste Serena is endorsing.

Not since Steffi Graf in 1994 has anyone held all four grand slam titles and never has Serena enjoyed such flattering comparisons - with Tiger Woods and Edwin Moses - in terms of the dominance of her sport.

Not since 2000 when Richard Williams announced that his daughter was considering retirement has there been so much doubt and speculation about the future of Venus. Her failure on her home patch here raises questions not just about her emotional state but her physical condition too.

"I tried, but I just couldn't seem to get the ball in today," she said, calmly disconsolate. "If I had played really well, there was a good chance that I could have won the match. All I can do is give her credit."

Shaughnessy did play well. She knew she should pressure Venus's second serve, she knew which was Venus's less consistent wing, and she hit some fine wrong-footing forehands. She has strengthened her game, she claims, with hypnosis, using CDs, and by adding 15lb of muscle in two years. "I live for times like these," she said.

But Venus is not the player who won the Wimbledon and US Open titles back to back two years ago. Her serve was depressingly vulnerable, she made mistakes on the fore hand, and she fell away badly in the second set. There was even one eye-catching moment near the end when a Shaughnessy stop volley lurched over the net and spun spectacularly back again.

Last year Venus had a wrist problem that forced her withdrawal from the Italian Open and a leg strain that caused her to retire during the WTA Tour year-end championships. Knees have been the problem recently. Ever since she took six months off in 1999-2000, troubled by tendinitis in both wrists, there have been concerns about how long her body would survive the battering she gives it.

For Venus has helped change the women's game. She was not quite the first to hit her ground strokes every time at full bore and maximum grunt. Monica Seles did that. But Venus at her best hit her first serve a wallop too and wore dresses with big shark bites out of the back that captured everyone's attention.

A generation of stronger, bigger and more aggressive women were encouraged to believe they could develop a consistently effective power game. Of those who could not, many decided that they must at least learn to hit hard enough not to relinquish the initiative to those who could. Arguably Venus was responsible for the improvement in Shaughnessy that overcame her.

But with her giraffe legs and awkward style she was always more vulnerable to injuries than most. Venus withdrew from the Dubai Open last month citing "her schedule" but is now not going to play again for a whole month, till the European clay-court season is under way. That is a lot of time off. The whisper suggests her body is still not right.

And there are question marks about her mind. It has many distractions. She is bright. She has an interior design business. She enjoys art. And she is expecting to publish a book of her poetry. Tennis is far from the only thing in her life, and maybe not the most important thing.

Last week Venus was hauled in at the last moment as a substitute for Serena at one of her many appearances. How many interior design business clients did she have, Venus was asked. "I have a few. My toughest client is Serena," she said laughingly. "She pressurises me."

It emerged that she would not be charging for these demands. "Serena kept saying I want to pay, I want to pay," Venus smilingly said. "But I won't let her." For Venus is prepared to accept Serena just the way she is. And maybe the way things are.