It's never too late: the 10th month of the WTA season saw a quartet of players make their mark in an exciting sprint through the end of the season.
From career firsts to statement victories, this group was responsible for results that made the WTA stand up and take notice throughout over the year's final weeks.
Have a look at the nominees and cast your vote before Thursday at 11:59pm ET! The winner will be announced Friday, November 10.
October 2017 Breakthrough of the Month Finalists
Carina Witthoeft: Unseeded Witthoeft raised her first career WTA trophy at the BGL Luxembourg Open, defeating No.8 seed Varvara Lepchenko and No.2 seed Kiki Bertens en route to the final, where she then beat Olympic gold medalist Monica Puig.
“Winning my first WTA title feels unbelievable,” Witthoeft said after the match. “I’m so happy now, it’s been a tough week, a tough final today. I’m just happy.
“To play the last tournament of the season and finish the season winning your first title is just perfect.”
The German ended her season at the highest of highs in her final tournament of the season: having previously reached three quarterfinals and one semifinal on the WTA this season, the 22-year-old took the next step headed into 2018.
Aryna Sabalenka: Coming into the Tianjin Open as ranked World No.119, Sabalenka defied all odds to make her first WTA final. She defeated three Chinese players - Han Xinyun, Duan Ying-Ying and Zhu Lin without the loss of a set to reach the semifinals, where she then rolled former French Open finalist and World No.5 Sara Errani.
In her first-ever WTA final, Sabalenka gave a great accounting of herself against childhood idol Maria Sharapova, building a 4-1 first set and 5-1 second set lead before eventually falling, 7-5, 7-6(8).
The week prior, the Belarusian teenager reached her first WTA semifinal in Tashkent in the final days of September.
Sabalenka's efforts in Tianjin propelled her into the Top 100 and moved her into the pole position of Belaurs' No.1. She will lead her country's effort in the upcoming Fed Cup final against the United States later this week.
Natalia Vikhlyantseva: There's something cooking at home for the Russian 20-year-old, who made her second Premier-level semifinal at the VTB Kremlin Cup in Moscow in October.
After reaching her first Premier semifinal at St. Petersburg in February, Vikhylantseva capped her season with another stellar result on Russian soil.
The Russian defeated US Open quarterfinalist and former Top 20 player Kaia Kanepi in the first round, before scoring her first-ever Top 20 win over compatriot Elena Vesnina followed in round two.
Vikhylantseva then defeated Alizé Cornet in the quarterfinals to again reach the final four, and though she saw her run ended by eventual champion Julia Goerges in a three-set semifinal, the Russian No.6 ends her season at a career-high ranking of World No.54.
Julia Goerges: The German caught fire in incredible fashion to end her 2017 season, winning her last nine matches to raise the trophies at the VTB Kremlin Cup and Hengqin Life WTA Elite Trophy Zhuhai in back-to-back weeks.
Goerges made three finals over the summer in Mallorca, Bucharest, and Washington D.C., before winning her first title in six years in Moscow over Daria Kasatkina.
She then proceeded to go undefeated in Zhuhai with wins over Kristina Mladenovic, Magdalena Rybarikova, Anastasija Sevastova, and CoCo Vandeweghe to rise to a career-high ranking of No.14 and supplant Angelique Kerber as German No.1.
January: CoCo Vandeweghe
February: Kristina Mladenovic
March: Risa Ozaki
April: Daria Kasatkina
May: Jelena Ostapenko
June: Magdalena Rybarikova
July: Bianca Andreescu
August: Sofia Kenin
September: Ashleigh Barty
How it works:
Finalists are selected by wtatennis.com
Winner is then determined by a fan vote on wtatennis.com