(Reuters) - Kiki Bertens topped her round robin group in convincing fashion with a 6-4 6-3 victory over Dayana Yastremska to become the first player to qualify for the semi-finals of the WTA Elite Trophy in Zhuhai, China on Thursday.
Both players had already beaten Croatia's Donna Vekic earlier this week, which made the final round robin match a virtual quarter-final where the Dutch top seed got the better of the 19-year-old Ukrainian.
Yastremska's poor service game in the opening set -- she made four double faults in three games -- opened the door for Bertens who broke her teenaged opponent five times in the encounter.
Although Yastremska also converted two break points, she was no match for Bertens' patient baseline game which forced the Ukrainian to make numerous errors and a fifth double fault on match point ended the contest.
"Changing the rhythm, I think that's what she doesn't like," Bertens told reporters. "She really likes that every ball is coming at the same height, at the same pace.
"So just throwing in some slices -- I think she's really struggling with that, I saw that already in Beijing and I think today again. That's what I normally do already, but I think that against players like Dayana, even more."
Earlier, the Czech Republic's Karolina Muchova fought back from a set down in her round robin opener to beat American Alison Riske 2-6 6-2 7-5.
Muchova, who converted six of 13 break points, was 3-1 down in the deciding set before clawing her way back into the tie to keep her semi-final hopes alive.
Meanwhile, American third seed Madison Keys overcame fifth seed Petra Martic of Croatia 6-3 6-4.
(Reporting by Rohith Nair in Bengaluru, editing by Pritha Sarkar)