Top seed Simona Halep defeated Alize Cornet in a tight two-set match to claim a spot in the semi-finals of the Garanti Koza WTA Tournament of Champions in Sofia, Bulgaria.
Halep came through 6-4 6-4 against the seventh seed in the round-robin competition to claim her 50th match win of the year, with the result not showing the close nature of the contest as Cornet repeatedly fought back before the Romanian edged her out.
"It was a really hard match - she played really well and really aggressively," Halep told wtatennis.com.
"I was a little bit nervous and it was a very physical match - I was getting tired - but I just tried to focus on every point, and my serve helped me a lot in the end today.
"I'm really happy to win the match today."
By securing victory against France's Cornet, along with becoming the first through to the semi-finals, Halep became only the fourth player to reach a half century of victories this year behind Serena Williams (78), Agnieszka Radwanska (56) and Petra Kvitova (51).
Roberta Vinci currently has 49 match wins and could also make it to 50 in Fed Cup this weekend.
In the other matches, fourth seed Samantha Stosur came through 6-3 6-3 against fifth seed Elena Vesnina, while Anastasia Pavlyuchenkova defeated Elina Svitolina 6-2 6-4.
On Thursday, Ana Ivanovic plays Stosur while Vesnina takes on Tsvetana Pironkova and Halep faces Svitolina.