Daria Gavrilova is on the verge of an Australian Open seeding after continuing her strong form in Moscow.
The Australian secured a quarter-finals berth in the Kremlin Cup after her Spanish opponent Carla Suarez Navarro retired from their second-round clash.
World No.37 Gavrilova was leading 6-4 3-0 when Suarez Navarro succumbed to a wrist injury.
Gavrilova is understood to require a quarter-final win against seventh-seeded Anastasia Pavlyuchenkova to boost her ranking into the top 32, giving her a seeding at her home tournament in January.
She rallied against world No.12 Suarez Navarro after going down a break early in the first set.
Gavrilova produced several superb winners to hit back from 4-3 down with her opponent on serve to win the next six games of the match.
"I thought I played pretty well. It was a tough battle," Gavrilova said.
"(There were) a few pretty tough games, I think we played the first four games for like 40 minutes, and then I found momentum.
"I lost my serve at the very beginning, but I felt like I was still in it and I had a lot of chances and then finally it all worked out.
The result comes after recent upset wins over top-ranked Angelique Kerber in Hong Kong and Lucie Safarova in Moscow.
"I feel very different to how I felt last year; I was really tired last year," Gavrilova said.
"This year, I had a few days off after the US Open and regrouped and had my training in Melbourne and now I'm just enjoying the last few tournaments."
The result has killed off Suarez Navarro's hopes of qualifying for the WTA Finals.
Top-seeded Svetlana Kuznetsova remains on course to claim the last WTA Finals place after she beat France's Alize Cornet 6-4 7-5 in their second-round match.
The Russian was in strong form, landing 76 per cent of her first serves, and next plays Hungarian Timea Babos, seeded ninth.
Kuznetsova will qualify for the WTA Finals only if she wins the Kremlin Cup. Otherwise, the place goes to Britain's Johanna Konta.
The fourth-seeded Elina Svitolina of Ukraine eased past Yulia Putintseva of Kazakhstan 6-2, 6-2 and into the quarterfinals. Svitolina next plays 18-year-old Croatian Ana Konjuh, who had a second-round walkover when Russian qualifier Anna Blinkova was unable to play.
