Ninth-seeded Alison Riske lost her first two service games of the match but bounced back to beat American countrywoman CoCo Vandeweghe 6-3, 6-4 on Monday in the first round of the Mubadala Silicon Valley Classic in San Jose, Calif.
Riske won the last six games of the first set and the first three games of the second set. Vandeweghe broke back to trail only 3-1 in the second set, then had three break points in what proved to be the final game before Riske closed out the win.
Other opening-day winners were sixth-seeded Petra Martic and Ana Konjuh of Croatia, Magda Linette of Poland, Shuai Zhang of China and Caroline Garcia of France.
Ukraine's Lesia Tsurenko upset one of the home-country favorites, beating fifth-seeded Elena-Gabriela Ruse 6-3, 6-3 in the first round at Cluj-Napoca, Romania.
Ruse put just 50 percent of her first serves in play and managed to win just four of the 12 break points her serve. Tsurenko had lost all five of her previous main-draw WTA Tour matches this year.
Sixth-seeded Slovenian Kaja Juvan routed Russia's Marina Melnikova 6-1, 6-1, and Spain's Lara Arruabarrena cruised past Romania's Evelyne Tiron 6-0, 6-0.
--Field Level Media