Madrid:Serena Williams' up-and-down season may well be over after she suffered yet another in a long list of injuries and was forced to retire from her opening match in the WTA Championships after losing one set to Anna Chakvetadze, the world number seven from Russia.
Williams, looking very upset, was taken to hospital for a scan yesterday and will not make a statement about her presence in the tournament until the results are known, although the odds look against her continuing.
There were signs that all was not well from the start, for Williams appeared with gigantic tapes down the front of both thighs and encircling her knees and it was not long before it became clear that her movement was limited.
Her error ratio was much higher than usual, and as it increased so did her distress, leading to a brief bout of tears and, eventually, at 4-5 causing her to call for the trainer.
This brought a ten-minute interval and some more taping, but only enabled her to contest seven more points.
Eventually after losing the set 6-4 it brought a retirement which also raises a question over the future of the American whose hard hitting helped change the women's game.
Later Serena claimed it was her intention to try to continue the tournament.
In a statement she said, "The funny thing was I thought I was tighter in the right knee and then in the match, once I had to increase my range of movement, the left knee got worse.
"I have had issues with my knees before, especially with my left knee since that's the one I had surgery on in 2003.
It's beyond unfortunate this has happened and I can't even stress how disappointed I am."
Although Williams won the Australian Open at the start of the year and determinedly climbed from 95 in the rankings to number five now, Williams has still looked short of the player who once held all four Grand Slams simultaneously.
She was suffering from knee problems while winning Miami in April, a groin problem when she withdrew from Charleston later that month, and a severe calf muscle spasm and a badly injured finger at Wimbledon.
She returned to play three European indoor tournaments in a row and ensure a place at the year-end championships this week, but again she was not at her best, although the abruptness of her retirement here still comes as a shock.
"Oh, well, so yeah, I just ran into bad luck," she answered when questioned about her fitness problems at the weekend.
"Like really, like I was on my way to glory and I ran into bad luck, so there's nothing I could do about it. I just literally fell, literally fell, just practically broke my thumb. And the chances of that happening are slim to none," she added, referring to the injury she sustained at Wimbledon.
This sounded like an attempt to maintain her morale when she said these words on Saturday. Now they seem as though she was whistling in the dark.
The result means that Justine Henin's attempt to finish the finest year of her career with a successful defence of her WTA Championships has already earned her a semi-final place.
Earlier the world number one from Belgium became the first player to win two matches, and was in wonderfully fluent form as she followed her first day straight sets win over Chakvetadze with a 6-2, 6-2 success over Jelena Jankovic, the world number three from Serbia.