Singapore (AFP) - Two-time defending champion Serena Williams beat Caroline Wozniacki of Denmark 2-6, 6-3, 7-6 (8/6) to reach the WTA Finals title match in Singapore on Saturday.The world number one posted her fourth win of the year against Wozniacki and will face either Simona Halep or Agnieszka Radwanska in Sunday's final.Join the conversation about this story »