As Serena Williams was escorted off the court for an injury timeout during her deflating loss to Maria Sharapova at the WTA Tour Championships in Los Angeles Monday night, ESPN’s esteemed tennis commentator, Cliff Drysdale, speculated that the former world no. 1 might be having trouble with her belly-button ring.

How fitting it seemed: The women who cares about on-court fashion as much as her footwork might have been dealt a fatal blow in the season-ending tournament by a piece of jewelry.

Of course, nothing of the sort had happened. Say what you will about Williams’s love for tennis boots, frilly skirts, and revealing tops; her problems in 2004 have been ones of substance, not style, and largely out of her control. First it was her knee, which required surgery, and now it is her abdominal muscle.

Williams fought valiantly against Sharapova, taking a 4-0 lead in the third set despite pushing 60 mph serves over the net like a local duffer. But she ran out of gas in a match that she would have been within her rights to withdraw from. She smiled, as she always does, when she collected her second-place trophy, but it was hard to mask her disappointment in losing a match – 4-6, 6-2, 6-4 – that would have brought a positive finish to a trying season.

Anything short of domination is seen as failure for Williams, and the fact remains that she can still win as many tournaments as anyone on the tour if she puts her mind to it and remains healthy. Still, Williams is unlikely to run the table as she once did. The crop of young Russians are improving and Justine Henin-Hardenne remains the most well-rounded player in the world (that is, if she licks a debilitating virus that halted her 2004 season). Williams should win at least one Grand Slam next year, most likely Wimbledon.

For Sharapova, defeating Williams was a stellar finish to a breakthrough season. She won Wimbledon over Williams earlier in the year, and this week survived a round-robin loss to Amelie Mauresmo on her way to the title. Against Williams Monday, she seemed done in the third set, but kept at it and allowed the injured Williams to give away point after point. When it was over, Sharapova fell slowly to the ground in one of the oddest victory poses in memory, her face blank and her body limp as if she had just been unplugged from an electrical outlet.

At age 17, Sharapova is now ranked fourth in the world and should contend for more Grand Slam titles next year. With a few improvements – speed, stamina and, most important, shot selection – she’ll contend for the no.1 ranking by next summer, though don’t be surprised if her countrywoman Svetlana Kuznetsova surpasses her.

Though she didn’t even make the semifinals, Lindsay Davenport ended up the week’s other big winner. Mauresmo’s semifinal loss left Davenport in the no. 1 spot, the third time she has ended a season with the top ranking. It also left the 28-year-old American talking positively about the Australian Open, rather than retirement.

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In Houston, the men’s year-end tournament – the Tennis Masters Cup – has been marred by rain delays this week. Playing his first tournament in a month, world no. 1 Roger Federer easily defeated clay-court specialist Gaston Gaudio, 6-1, 7-6(4) after a few hours of delays. Federer, sporting a new haircut, showed no ill effects from a recent thigh muscle injury and is looking to defend the title he won here last year.

In other round-robin action, Lleyton Hewitt beat Carlos Moya in three sets yesterday, 6-7(5), 6-2, 6-4. The first set was interrupted by rain with Hewitt leading, but Moya recovered to win a tiebreak, saving a set point. From there on, Hewitt was his usual unrelenting self, striking 39 winners and never facing a break point. He should earn one of two semifinal spots from his group, which includes Federer, Moya, and Gaudio.

Later yesterday, Marat Safin continued his resurgence with a 6-1, 6-4 victory over Guillermo Coria. Safin served seven aces and needed only an hour to secure a victory. The former no.1 is likely to reach the semifinals in his group along with Andy Roddick, though one can never count out certified Roddick nemesis Tim Henman.