(Reuters) - Karolina Pliskova advanced to the semi-finals of the Bank of the West Classic with a 6-2 6-4 win over Croatia's Ajla Tomljanovic on Friday.
The world number 11 will meet American Varvara Lepchenko in the semi-finals on Saturday while Ukraine's Elina Svitolina will play Germany's Angelique Kerber at the tournament in Stanford.
Lepchenko defeated Mona Barthel of Germany 6-7 6-2 6-3 while Svitolina advanced with a 4-6 7-5 6-1 win over American Alison Riske.
Germany's Kerber came from behind to beat Poland's second seed Agnieszka Radwanska 4-6 6-4 6-4.
Win or lose Pliskova will push herself into the top-10 for the first time when the new rankings are released on Monday.
Only world number one Serena Williams (40-1) has won more matches than Pliskova (38-14) this season.
(Editing by Greg Stutchbury)