Wozniacki topples Serena from top spot

Caroline Wozniacki of Denmark kisses the trophy after securing the world number 1 ranking on the WTA Tour after her win over Petra Kvitova the Czech Republic during day seven of the 2010 China Open in Beijing. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: Getty Images

Caroline Wozniacki of Denmark kisses the trophy after securing the world number 1 ranking on the WTA Tour after her win over Petra Kvitova the Czech Republic during day seven of the 2010 China Open in Beijing. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: Getty Images

Denmark's Caroline Wozniacki serves against Petra Kvitova of the Czech Republic during their women's single in the China Open tennis tournament at the National Tennis Centre in Beijing, China. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: AP

Denmark's Caroline Wozniacki returns a ball against Petra Kvitova of the Czech Republic during their women's single in the China Open tournament at the National Tennis Centre in Beijing. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: AP

Caroline Wozniacki of Denmark returns the ball to Petra Kvitova of the Czech Republic during their third round match at the China Open tournament in Beijing. Wozniacki became the first Danish tennis player to be crowned world number one when she beat Kvitova to reach the quarter-finals of the China Open, dethroning American Serena Williams. Photo: Reuters

Caroline Wozniacki of Denmark poses for photographers after securing the world number 1 ranking on the WTA Tour after her win over Petra Kvitova the Czech Republic during day seven of the 2010 China Open in Beijing. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: Getty Images

Top-ranked women's tennis player Caroline Wozniacki will have to fight to keep her No.1. ranking at the WTA Championships in Doha.

Denmark's Caroline Wozniacki holds a no 1 shape bouquet of flowers after defeating Czech Republic's Petra Kvitova in their women's single in the China Open tennis tournament at the National Tennis Centre in Beijing, China. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams, who has not played since winning her 13th grand slam title at Wimbledon in July. Photo: AP

Denmark's Caroline Wozniacki holds up a number one trophy after defeating Petra Kvitova of the Czech Republic in their women's single in the China Open tennis tournament at the National Tennis Centre in Beijing. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: AP

Caroline Wozniacki of Denmark is toasted in the players lounge to commerate her capturing the world number 1 ranking on the WTA Tour after her win over Petra Kvitova the Czech Republic during day seven of the 2010 China Open in Beijing, China. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: Getty Images

Caroline Wozniacki of Denmark celebrates in the players lounge with Danish fans after she captured the world number 1 ranking on the WTA Tour after her win over Petra Kvitova the Czech Republic during day seven of the 2010 China Open in Beijing, China. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: Getty Images

Caroline Wozniacki of Denmark celebrates in the players lounge with Danish Ambassador Friis Arne Petersen after she captured the world number 1 ranking on the WTA Tour after her win over Petra Kvitova the Czech Republic during day seven of the 2010 China Open in Beijing, China. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams. Photo: Getty Images

Denmark's Caroline Wozniacki poses for photographers after her win over Petra Kvitova of the Czech Republic during day seven of the 2010 China Open at the National Tennis Centre in Beijing, China. Wozniacki became the first Danish tennis player to be crowned world number one after dethroning American Serena Williams, who has not played since winning her 13th grand slam title at Wimbledon in July. Photo: Getty Images