Kostyuk reaches Guadalajara quarters without striking a ball

Marta Kostyuk is into the Guadalajara Open quarter-finals without hitting a competitive ball.

The Ukrainian top seed, ranked world No 10, was due to start her campaign on Wednesday against Taylor Townsend in Mexico. Townsend withdrew through illness, handing Kostyuk a walkover, a win awarded without playing, and a place in the last eight BBC Sport.

Kostyuk had already sat out the opening round. She received a first-round bye, the free pass given to the leading seeds that holds them back until the second round and stops the top players meeting each other too early.

She will now face eighth seed Liudmila Samsonova for a place in the semi-finals. Samsonova earned her spot the hard way, beating American Kayla Day 7-6 (7-4), 2-6, 7-6 (7-5) BBC Sport.

That match was a grind. Day took the second set at a canter and pushed both other sets to tie-breaks, the first-to-seven shootouts used to settle a set locked at 6-6. Samsonova held her nerve twice, closing the first 7-4 on points and the decider 7-5.

The contrast is stark. Kostyuk arrives fresh. Samsonova arrives tested.

Kostyuk has the season to justify her top billing. She claimed her maiden WTA 1000 title, the tier of event just below the four Grand Slams, in Madrid in May. She then reached the semi-finals at both the French Open and Wimbledon. Her most recent match was a defeat to sixth seed Linda Noskova in the last 16 of the US Open.

The Guadalajara tournament is a WTA 500 event, a mid-level stop on the women's tour, played on hard courts and running from 13 to 19 September WTA.

For fans, this means a strange kind of test. Kostyuk will have rhythm to find and energy to spare. Samsonova will have rhythm banked and heavy legs to manage. Sometimes the wall gives you nothing. Sometimes it gives you everything.