Caroline Wozniacki's troubles continue.

Caroline Wozniacki is preparing for a double celebration. The 21-year-old Dane hopes to secure her first title of the year here at the Dubai Duty Free Championships and believes she is also on course to win a bet she has struck with her boyfriend, Rory McIlroy.

Victoria Azarenka has won all her 17 matches this year, but the season is already taking its toll on the new world No 1. Having injured an ankle en route to winning the Qatar Open last weekend, the Australian Open champion today pulled out of the Dubai Duty Free Championships here just hours before she was due to play her first match, against Julia Goerges.

The very idea of an organisation here in the United Arab Emirates choosing to invite an Israeli to take part in a sporting event is highly improbable, given that there are no diplomatic relations between the two countries. The idea of such an invitation being extended to an Israeli once at the centre of a furore that threatened the future of one of the UAE's most important competitions might have seemed even more unlikely – but exactly that scenario is being played out here at this week's Dubai Duty Free Championships.

It would hardly have felt like consolation at the time, but at least Caroline Wozniacki could take one positive from her 6-3, 7-6 defeat by Kim Clijsters in the quarter-finals of the Australian Open yesterday. The 21-year-old Dane's exit from the tournament means that, for the moment at least, she will not have to answer questions about whether she deserves to be world No 1 when she has yet to win a Grand Slam tournament.

Caroline Wozniacki again attempted to play down the significance of her number one ranking despite edging closer to retaining top spot with a routine win over Monica Niculescu at the Australian Open today.

Victoria Azarenka led a quintet of leading players in cruising into the second round of the Australian Open today.

Kim Clijsters today shrugged off any concerns over a hip injury and declared herself "ready to go" as she prepares to defend her Australian Open crown.

Britain's Andy Murray will attempt to continue his autumn winning run in Roger Federer's hometown tournament of Basle next week. Murray (right), who has just replaced the Swiss at No 3 in the world rankings after winning his last three tournaments, has taken a wild card into the tournament. A highly competitive field includes Federer, Novak Djokovic, Andy Roddick, Mardy Fish and Tomas Berdych.

Kim Clijsters blamed a loss of confidence for her shock second-round defeat by Arantxa Rus at the French Open today.

It's been nearly a year since Francesca Schiavone dropped down to kiss the clay court following her memorable French Open victory.

Kim Clijsters admitted she ran out of "fighting spirit" as she lost to Victoria Azarenka in the quarter-finals of the Sony Ericsson Open in Miami.

At the start of this week Caroline Wozniacki was expressing relief at no longer having to comment on whether she deserved to be world No 1 given that she has never won a Grand Slam title. Come Monday the 20-year-old Dane will be bracing herself for another round of questions along the same lines. Wozniacki's 6-2, 6-4 victory here yesterday over Shahar Peer in the quarter-finals of the Dubai Duty Free Championships ensured that she will return to the top in next week's updated rankings list, just seven days after being overtaken by Kim Clijsters.

Kim Clijsters is confident of producing the improved performance she feels is required to beat Vera Zvonareva in the Australian Open semi-finals tomorrow.