MONTERREY, Mexico -- Top-seeded Danielle Collins is out of the WTA 500 event in Monterrey, beaten 1-6, 6-3, 6-3 by Erika Andreeva in a match that finished about 1 a.m. Wednesday at the hardcourt tournament in Mexico.
Andreeva beat a top 20 player for the first time to advance to the quarterfinals of a top-level WTA tournament, also for the first time.
Earlier, sixth-seeded Linda Noskova dropped just one game in a 49-minute, 6-0, 6-1 win Tuesday over Anna Danilina of Kazakhstan to reach the round of 16.
The 19-year-old Czech player will next meet either Wang Xiyu of China or Germany's Tatjana Maria.
Defending champion Donna Vekic withdrew from the Monterrey tournament after winning the Olympic silver medal in Paris.