Marta Kostyuk is through to the quarter-finals of the Guadalajara Open even though the top seed is yet to play a point in the tournament.

The Ukrainian received a first-round bye in Mexico and got a walkover in her scheduled second-round match on Wednesday, when Taylor Townsend withdrew because of an illness.

Kostyuk, the world number 10, is now scheduled to get her tournament under way against the eighth-seeded Liudmila Samsonova of Russia, who edged Kayla Day 7-6 (7-4) 2-6 7-6 (7-5).

Kostyuk claimed her maiden WTA 1000 title in Madrid in May and has reached the semi-finals of the French Open and Wimbledon this year.

Most recently the 24-year-old lost to sixth seed Linda Noskova in the last 16 of the US Open.