January was defined by four breakthrough players who brought some impressive performances on and off the court. Which one soared the highest?

Have a look at the nominees for January’s Breakthrough of the Month and cast your vote before Thursday at 11:59pm ET! The winner will be announced Friday, February 3.

January 2017 WTA Breakthrough of the Month Finalists:

Katerina Siniakova: Siniakova started the season at the Shenzhen Open, where she won her first title with wins over Simona Halep and Johanna Konta before knocking out 2016 finalist Alison Riske in the championship match. The win brought the Czech youngster to a career-high ranking of No.37.

Elise Mertens: Mertens made her Top 100 debut after winning the Hobart International the week before the Australian Open. Though she missed the deadline for Melbourne qualifying, the powerful Belgian blew through the draw, roaring through qualifying to defeat top seed Kiki Bertens and Monica Niculescu in the final.

Lauren Davis: Another player to take home their maiden WTA title was young American Lauren Davis, who started the year at the ASB Classic. Unseeded in Auckland, Davis beat four seeds to the title, including Bertens, Barbora Strycova, Jelena Ostapenko, and Ana Konjuh.

CoCo Vandeweghe: Vandeweghe made her major breakthrough at the Australian Open, getting back-to-back wins over two of 2016’s three Grand Slam champions in World No.1 Angelique Kerber and Garbiñe Muguruza. Making her first Grand Slam semifinal, the American pushed eventual finalist Venus Williams to three tough sets.

2016 Winners:

January: Zhang Shuai
February: Jelena Ostapenko
March: Nicole Gibbs
April: Cagla Buyukakcay
May: Kiki Bertens
June: Elena Vesnina
July: Kristina Kucova
August: Karolina Pliskova
September: Naomi Osaka
October: Peng Shuai

How it works:

Finalists are selected by wtatennis.com
Winner is then determined by a fan vote on wtatennis.com