Three first-time title-winners highlight the ballot for April's Breakthrough of the Month, but we need your votes to determine who was truly the best.
Have a look at the nominees and cast your votes by Thursday, May 9 at 11:59 p.m. EST to help us determine this month's winner.
Amanda Anisimova: Having skipped the clay court season the previous year due to injury, Anisimova entered the Copa Colsanitas in Colombia without any match wins on clay at the WTA level.
Nonetheless, she walked away with the trophy for her first career title.
Read more: 'It's a huge deal' - Anisimova revels in first WTA title after Bogota epic
As the No.6 seed, she won four of her five matches in three sets, including the final against fellow debutant Astra Sharma.
Anisimova rallied from a set and a break down in the championship match, in a tournament where she also came from a set down against Sabine Lisicki in the first round and Beatriz Hadda Maia in the quarterfinals.
Maria Sakkari: Another first-time title-winner in April, Sakkari won the Grand Prix De SAR La Princesse Lalla Meryem in Rabat, coming from a set and a break down to defeat Johanna Konta in the final.
Greece's No.1 hadn't dropped a set en route to the final, defeating Olga Danilovic, Isabella Shinikova, defending champion and top seed Elise Mertens and another Belgian in Alison van Uytvanck en route to the championship match.
Jil Teichmann: The 21-year-old Swiss qualifier came to the J&T Banka Prague Open having never before reached a WTA quarterfinal and left with her first WTA title.
Among her victories over the course of the week was a thrilling three-set second-round comeback against two-time Grand Slam champion and former World No.2 Svetlana Kuznetsova, and a statement 6-3, 6-0 win over No.9 seed Barbora Strycova in the semifinals.
The former junior World No.3 became the first player in five editions of the tournament to win the title after winning the first set, as each of the past four champions had to rally from a set down to win the trophy.
Karolina Muchova: A wildcard at the J&T Banka Prague Open, Muchova had a banner week on home soil to reach her first WTA final and crack the Top 100 for the first time in her career.
The beneficiary of Lucie Safarova's decision to turn down a farewell singles wildcard in Prague, Muchova repaid her compatriot by becoming the sixth Czech to reach the final at the International-level event, defeating rising Pole Iga Swiatek, Jennifer Brady, Natalia Vikhlyantseva, and Bernarda Pera before falling the Teichmann.
The winner will be announced on Friday, May 10.
How it works:
Finalists are selected by wtatennis.com
Winner is then determined by a fan vote on wtatennis.com
Previous WTA Breakthroughs of the Month for 2019
January: Dayana Yastremska
February: Hsieh Su-wei
March: Bianca Andreescu