PERTH • Despite Serena Williams' efforts to play down the effects of her latest injury, doubts over her Australian Open title defence are growing.
The world No. 1 yesterday pulled out of the mixed-teams Hopman Cup in Perth due to a knee problem - just a day after refusing to rule herself out of the tie against the Czech Republic.
"(It needs) a little rest, a little treatment," she said on Tuesday after retiring from her first singles match against Australian Jarmila Wolfe.
"I've been training really hard during the off-season and really pushing myself beyond the limits, I just think a day off or two will make a world of difference."
Yet, she failed to take to the court yesterday.
She had already missed the United States' opening Hopman Cup tie due to inflammation of her left knee before attempting to play against Wolfe.
When informing Hopman Cup organisers of her withdrawal from the tournament, however, the Williams camp said it believed she would be fine after a couple of days' rest.
The 34-year-old, who battled knee problems in the latter half of last year, is seeking to win a 22nd Grand Slam title at the Jan 18-31 Australian Open.
A seventh title in Melbourne will see her equal Steffi Graf's record of 22 Grand Slam singles titles in the professional era.
Andy Murray's preparations for the year's first Grand Slam also suffered a setback at the Hopman Cup yesterday when the world No. 2 went down in straight sets to local favourite Nick Kyrgios.
Murray, who led Britain to their first Davis Cup triumph in 79 years just over a month ago, stormed past France's Kenny de Schepper in his opening match of the mixed teams event on Monday but did not seem to be at his 100 per cent against Kyrgios.
The 20-year-old Australian, ranked 30th in the world, had never won his previous four meetings against Murray, including three losses in Grand Slams last year.
But he salvaged some pride with a 6-4, 7-6 (7-5) win to give his team, Australia Green, a 1-0 lead against Britain.
"I did promise a few of my friends that next time I played Murray I would beat him, and there you go," Kyrgios said at a court-side interview after his win.
"I've improved a lot. I've put a lot of hard work over the off-season and it has paid off."
In Doha, defending champion David Ferrer crashed out in the first round of the Qatar Open on Tuesday, beaten in three sets by Ukraine's Ilya Marchenko.
Ferrer, the No. 4 seed, struggled throughout, losing his serve in the very first game, hitting 43 unforced errors and eventually going down 7-6 (8-6), 3-6, 2-6 in an eventful clash lasting over 21/4 hours.
Before Tuesday, world No. 94 Marchenko had never won a set against a top 10 player.
"He was better than me all the match. From the first set, he deserved to win the match," said a gracious Ferrer, the world No. 7.
The Spaniard played with a new racket but did not blame it for his loss.
AGENCE FRANCE-PRESSE, REUTERS
Australia Gold v Ukraine: Singtel TV Ch115 & StarHub Ch209, 10am
Czech Republic v USA: 5.30pm