Shnaider won six straight games in the first set and came back from a 2-0 hole in the second set to win in 75 minutes. She broke Liu's serve six times in eight chances.

Also falling on the first day of the main draw was sixth seed Linda Fruhvirtova of the Czech Republic. Denmark's Clara Tauson eliminated Fruhvirtova 6-2, 7-6 (6).

Number one seed Magda Linette of Poland avoided a similar fate, rallying past Jodie Burrage of Great Britain 6-7 (3), 6-0, 6-2.

Number five seed Rebeka Masarova of Spain, No. seven seed Greet Minnen of Belgium and Harriet Dart of Great Britain also won their opening matches.

Guadalajara Open Akron

Hailey Baptiste, a Washington, DC, native, saved a match point while rallying for a 7-6 (5), 5-7, 7-6 (4) win over 16th-seeded Karolina Pliskova in second-round action at Guadalajara, Mexico.

Baptiste, who is ranked 174th in the world, is through to the third round of a WTA event higher than the 125 level for the first time in her career.

Pliskova, from the Czech Republic, led 5-2 in the third set and had a match point at 5-4, 40-30 but couldn't convert.

In other second-round matches, Martina Trevisan upset 15th-seeded Jasmine Paolini 7-5, 6-2 in an all-Italian matchup, and seventh-seeded Veronika Kudermetova of Russia downed Canada's Eugenie Bouchard 6-2, 6-7 (4), 6-4.

First-round winners included 10th-seeded Victoria Azarenka of Belarus and the United States' Caroline Dolehide, Emma Navarro, Sofia Kenin and Sachia Vickery. Colombia's Emiliana Arango knocked out 11th-seeded Russian Anastasia Potapova 6-4, 6-3, and Italy's Camila Giorgi defeated Egypt's Mayar Sherif, the No. 14 seed, 7-5, 6-3.