It's down to the semifinals of the BNP Paribas WTA Finals Singapore presented by SC Global - here are 10 things to look out for as the WTA stars keep battling it out for year-end glory!
(Singles play begins at 2:30pm Singapore time - see TV listings here)
(1) Serena Williams (USA #1) vs (8) Caroline Wozniacki (DEN #8)
Head-To-Head: Serena leads Wozniacki, 9-1
1) Serena dominates Wozniacki in their head-to-head, but that's deceptive.
The head-to-head seems lopsided but four of Serena's wins were three-setters, including one where she had to save three match points (Sydney in 2009) and two this year (in Montréal and Cincinnati).
2) Wozniacki is the only player who went perfect in the round robin here.
Wozniacki defied the seeds - she was the last one in at No.8 - and was the only player who went 3-0 in the round robin, scoring wins over Maria Sharapova, Petra Kvitova and Radwanska. Her wins over the No.2-ranked Sharapova and No.3-ranked Kvitova made this the first time she has ever beaten multiple Top 5 players at the same tournament - could she raise the bar with her third of the week today?
3) Wozniacki is looking for the biggest win of her career.
She spent 67 career weeks at No.1 in the world herself, but Wozniacki has never beaten a reigning World No.1, going 0-5 (which includes one loss to Dinara Safina and four losses to Serena).
4) Serena clinched year-end World No.1 yesterday.
The only player who could have taken No.1 from Serena here was Sharapova, but she needed to win the title and Serena to fall before the final - the Russian is already out, so year-end No.1 is Serena's.
5) Wozniacki is trying to become the third player to reach 50 wins on the year.
Going into today, just two players have 50 or more WTA-level match wins on the year - Ana Ivanovic, who has 58, and Serena, who has 50. Wozniacki and Carla Suárez Navarro are right behind with 49.
(4) Simona Halep (ROU #4) vs (6) Agnieszka Radwanska (POL #6)
Head-To-Head: Radwanska leads Halep, 4-2
6) Both are trying to become the first from their countries to reach the WTA Finals final.
Halep is trying to become the first Romanian to reach the final of the WTA Finals - only one Romanian has been to the semifinals here (Irina Spirlea, who was a semifinalist in 1997 and 1998). Radwanska is the only Polish player ever to play the WTA Finals and is going for her first final here today.
7) Radwanska is trying to be the first player to win the title here with a 1-2 round robin record.
Since the round robin format was introduced in 2003, only four players have advanced out of the round robin portion with a 1-2 record - Amélie Mauresmo (2003), Venus Williams (2009), Vera Zvonareva (2011) and Jelena Jankovic (2013). Mauresmo and Williams lost in the final, the other two in the semis.
8) Radwanska leads the overall head-to-head, but they're 1-1 this year.
Halep and Radwanska played each other twice earlier this year, just a few weeks apart actually, in the semifinals of Doha (which Halep won) and the semifinals of Indian Wells (which Radwanska won).
The doubles semifinals are also today...
(2) Hsieh/Peng (TPE/CHN) vs Kudryavtseva/Rodionova (RUS/AUS)
Head-To-Head: First Meeting
9) This is the first first-time meeting of the entire tournament.
All the singles players had played each other at least once before this week, and none of the four doubles quarterfinals or the other doubles semifinal are first-time meetings. The only potential other first-time meeting here would be a final between Black and Mirza and Kudryavtseva and Rodionova.
(3) Black/Mirza (ZIM/IND) vs Peschke/Srebotnik (CZE/SLO)
Head-To-Head: Black/Mirza lead Peschke/Srebotnik, 1-0
10) These two teams played once before but it was seven months ago.
Black and Mirza beat Peschke and Srebotnik in the only previous meeting between these two teams in the quarterfinals of Miami earlier this year. They won the match in straight sets, 6-4, 6-3.