The unseeded Putintseva eliminated third seed Tatjana Maria of Germany 6-4, 6-7 (6), 6-0. Putintseva converted six of 12 break points and saved nine of 11, overcoming Maria's 6-1 edge in aces.

Minnen, the seventh seed, ousted fourth seed Lucia Bronzetti of Italy 6-7 (8), 6-4, 6-1.

Top seed Magda Linette of Poland avoided the upset in defeating fifth seed Rebeka Masarova of Spain 7-5, 7-6 (6).

In the other quarterfinal between unseeded players, China's Xiyu Wang needed three sets to get past Slovakian Viktoria Hruncakova 6-4, 4-6, 6-3.

Minnen faces Wang in one semifinal Friday, while Linette plays Putintseva.

Guadalajara Open Akron

American Caroline Dolehide overcame an early deficit to oust a confident Martina Trevisan of Italy 3-6, 7-6 (9), 6-3 on Thursday in the quarterfinals in Guadalajara, Mexico.

Dolehide won 57 of 81 first-service points and saved eight of 12 break points to get past Trevisan, who eliminated top-seeded Tunisian Ons Jabeur on Wednesday. Dolehide also fended off a match point in the second-set tiebreaker before winning three straight points to a force a third set that she ultimately prevailed in.

In the semifinals, Dolehide will face countrywoman Sofia Kenin, who was a 6-4, 6-7 (6), 6-1 winner over Canada's Leylah Fernandez on Thursday.

Greek number two seed Maria Sakkari beat Colombia's Emiliana Arango 6-3, 6-4 and third-seeded Caroline Garcia of France beat 10th-seeded Belarusian Victoria Azarenka by an identical score in the day's other quarterfinal matches.