Dinara Safina photo Dinara Safina regained the World No. 1 ranking on Monday, October 26, 2009, taking over the spot from Serena Williams just in time for the Sony Ericsson Championships, which begins play on Tuesday, Oct. 27, 2009.

The Sony Ericsson Championships is a unique tournament, both in the way the players are determined, and in the way the format is played. The tournament draw consists of only the top eight singles players and the top four doubles teams from the 2009 Sony Ericsson WTA Tour season. They now compete for the coveted Sony Ericsson Championships title and a share of the record $4.55 million prize money. Prize money like that would make all the hard work of the past season really worth the effort.

The singles draw this year consists of Dinara Safina, Serena Williams, Elena Dementieva, Caroline Wozniacki, Svetlana Kuznetsova, Victoria Azarenka, Venus Williams, and Jelena Jankovic.

The doubles draw includes Cara Black/Liezel Huber, Venus Williams/Serena Williams, Nuria Llagostera Vives/Maria Jose Martinez Sanchez, and Rennae Stubbs/Samantha Stosur.

The tournament begins with a Round Robin format. The eight women in the singles event have been divided into two teams of four – the maroon group and the white group. From Tuesday through Friday, the players in each group will compete against each other in a round robin format. The two players with the best results from each group will advance to Saturday’s semifinals. The semifinals will be played with the first-placed woman from one group playing the second-placed woman from the other, with the two winners advancing to Sunday’s final. All the matches are played to best-of-three sets.

The four-team doubles competition is a straight-forward, single elimination draw. You can follow the singles action daily on The Tennis Channel.