WTA Finals

Wozniacki has enjoyed a fine season having reached seven finals but she has the chance to claim the biggest title of her career after a 7-6 6-3 victory over Karolina Pliskova on Saturday in the opening semi-final.

The Dane lost in the final of this even in Doha in 2010 and has also suffered defeat in two US Open finals but she continued her week in Singapore with a dominant display to end Pliskova's season and year-end no 1 dream.

The American world No 5 advanced to her fifth semi-final at the season finale after a determined 7-5 6-4 victory in one hour and 41 minutes.

Wiliams' win, which acts as some form of revenge for her Wimbledon final defeat to Muguruza, sees her finish second in the White Group behind Karolina Pliskova and the seven-time Grand Slam champion will next meet either Caroline Wozniacki or Caroline Garcia.

The match, lasting 3 hours, 13 minutes, featured 20 service breaks, with neither player finding much confidence on their service games.

The 37-year-old Williams dropped her serve nine times, while the 20-year-old French Open champion conceded serve 11 times.

"I don't know if there was any luck for me tonight, I just had to work for every point,'' the fifth-seeded Williams said. "It's not easy to lose the first match, and both of us were in the same situation. What else can you do but fight to live another day?''