
Garbine Muguruza —
Muguruza won her second grand slam title at Wimbledon in July, beating Venus Williams in the final.

Simona Halep —
The fifth woman to hold down the No. 1 ranking this year, Halep reached a second French Open final where she lost a thriller to Jelena Ostapenko.

Karolina Pliskova —
The ace leader this season, Pliskova sizzled at the start of the season before cooling off in the second half.

Elina Svitolina —
Svitolina is one of three players making their debut in Singapore. The Ukrainian has played in five finals in 2017 -- winning all of them.

Caroline Wozniacki —
The Dane endured an injury plagued 2016 but has been mostly healthy in 2017. Wozniacki has appeared in seven finals this season.

Venus Williams —
No one picked up more grand slam wins this season than Venus. She reached finals at the Australian Open and Wimbledon and the semis in New York.

Jelena Ostapenko —
Ostapenko's first title ... came at the French Open. The Latvian became the first unseeded woman to win Roland Garros since 1933.

Caroline Garcia —
Garcia -- who thrived in the juniors -- overtook Johanna Konta for the final place in Singapore by winning back-to-back titles in Wuhan and Beijing.