Karolina Pliskova advanced to her tour-best fifth final of the year, beating American Varvara Lepchenko 6-2, 7-5 on Saturday in the Bank of the West Classic.

The fourth-seeded Pliskova, from the Czech Republic, recorded her 39th victory of the season, one shy of leader Serena Williams. Pliskova will make her top-10 debut when the rankings are released Monday.

In her previous four finals appearances this year, Pliskova won in Prague and lost in Sydney, Dubai and Birmingham, England.

Pliskova averaged 105 mph on her first serve and had five aces en route to winning 81 percent of her first-serve points.

Lepchenko, who knocked off top seed Carolina Wozniacki in the second round, committed 50 errors — 24 of them unforced.

Fifth-seeded Angelique Kerber of Germany faced eighth-seeded Elina Svitolina of Ukraine in the second semifinal.