CINCINNATI, OH, USA - World No.2 Simona Halep edged ahead of the currently top-ranked Karolina Pliskova in the battle for supremacy on the WTA rankings, but the Romanian will need to win the Western & Southern Open to usurp the Czech and become the 24th woman in WTA history to reach WTA World No.1.
Halep started the week as one of five women who could have potentially become No.1 in Cincinnati, including Pliskova, former No.1s Angelique Kerber and Caroline Wozniacki, and Rogers Cup champion Elina Svitolina. That list narrowed as Pliskova advanced and Kerber fell to resurgent Russian Ekaterina Makarova.
Svitolina's loss to Germany's Julia Goerges brought the race down to two women; had both Pliskova and Halep made the final, the winner would have not only won the title in Cincinnati, but also emerged as World No.1.
Pliskova's loss to reigning Wimbledon champion Garbiñe Muguruza opens the door for the Romanian, who will have a fourth chance to become No.1 since Roland Garros, where she narrowly lost to Jelena Ostapenko in the championship match. She was also two points from leapfrogging Pliskova - and preventing the Czech powerhouse from ascending to No.1 in the first place - during the Wimbledon quarterfinals before eventually bowing out to British No.1 Johanna Konta.
Halep trails her head-to-head with Muguruza 2-1, having won their most recent meeting at the 2015 Porsche Tennis Grand Prix, but lost both hardcourt encounters in Fed Cup and the Dongfeng Motor Wuhan Open in 2014.
The Western & Southern Open women's final takes place at 2pm local time.