Victories for No.8 seed Daria Kasatkina and wildcard Margarita Gasparyan on Day 4 of the St. Petersburg Ladies Trophy guaranteed seven Russians in the quarterfinals of the tournament, the highest number in WTA history.

The pair succeeded in contrasting styles: Gasparyan held off Katerina Siniakova 6-4, 6-4 before Kasatkina emerged on top of a 5-7, 6-3, 7-6(2) knife-edge epic over Aliaksandra Sasnovich in two hours and 49 minutes. 

With No.2 seed Veronika Kudermetova and qualifier Anastasia Gasanova winning all-Russian derbies in the night session, there are more Russians in a WTA quarterfinal lineup than ever before. The previous record was six, set at Moscow 2005 where Dinara Safina and Elena Dementieva were semifinalists, while Kuznetsova, Maria Sharapova, Anastasia Myskina and Elena Likhovtseva reached the last eight.

Margarita Gasparyan reached her biggest quarterfinal since Moscow 2015 at the 2021 St. Petersburg Ladies Trophy.

Jimmie48/WTA

The last time any nation dominated a quarterfinal lineup was at Oakland 1993, where seven of the last eight were American: quarterfinalists Caroline Kuhlman, Ann Grossman and Mary Joe Fernandez, semifinalists Lindsay Davenport and Lori McNeil, runner-up Zina Garrison and eventual champion Martina Navratilova.

Kasatkina needed to survive an unpredictable ride against a mercurial opponent in which there was no shortage of plot twists. Sasnovich ran hot and cold with her ballstriking, but a barrage of 46 winners took the Belarusian to the brink of victory when she served for the match at 6-5 in the final set.

Despite trailing for almost the whole match, Kasatkina's tenacity and tactical adjustments kept her on Sasnovich's heels throughout. Sasnovich got off to a lightning start, boldly taking on drive volleys at every opportunity and showing fortitude of her own. Though the World No.97 was pegged back from 3-0 to 3-3 and 5-3 to 5-5 in the first set, a hold from 0-40 down at both junctures saw her regain the advantage and ultimately the 66-minute opening act, which Sasnovich sealed with a forehand winner after a 30-stroke rally.

Kasatkina was sharper in taking her chances in the second set, winning her first 11 return points as Sasnovich's service deflated. As the former World No.10 pulled into a 5-1 lead, she showed off the full range of her repertoire in essaying a pair of breathtaking forehand slice winners at full stretch.

An undaunted Sasnovich hit another purple patch in the closing stages of the second set, and though it was too late to save it the two-time WTA finalist took her momentum into the decider to capture the first break. Sasnovich also faced down a match point serving at 4-5 thanks to another daring drive volley.

But three of Sasnovich's 31 unforced errors came when she stepped up to serve for the match, and Kasatkina dominated the ensuing tiebreak. Striking her forehand with renewed aggression, the former World No.10 was clutch in closing out her fifth win over Sasnovich in eight meetings.

Earlier, Gasparyan had also shown resilience in her win over Siniakova. Two near-identical sets saw the World No.126 forge ahead with the first break, only for Siniakova to break back. Each time, Gasparyan raised her own game to break the Czech again and serve out each set emphatically.

Pulling off a series of crowd-pleasing single-handed backhand winners down the line, Gasparyan booked her place in her first WTA quarterfinal since Luxembourg 2019, and second at 500/Premier level following Moscow 2015. The 26-year-old's win also guarantees a home finalist from the top half of the draw: the only remaining non-Russian is Romanian qualifier Jaqueline Cristian, who faces No.4 seed Svetlana Kuznetsova in the third quarter.

As noted earlier, the final two matches of the day were both all-Russian affairs, so the surge of seven Russian quarterfinalists was settled midway through Thursday.

Less assured was that both of the late matches would, like Kasatkina's, go the distance -- although the whisker-thin wins by qualifier Gasanova and No.2 seed Kudermetova over their compatriots extended the pattern of marathon matches during the week.

First came Gasanova's 1-6, 7-6(8), 7-6(4) upset of No.5 seed Anastasia Pavlyuchenkova, where the qualifier saved three match points in the second-set tiebreak and advanced to her first-ever WTA singles quarterfinal.

"It's, of course, a very important match for me," Gasanova said. "I just reminded myself that I can beat the high-level players."

21-year-old Gasanova claimed her second straight barnburner victory with her three-hour and nine-minute win over two-time St. Petersburg quarterfinalist Pavlyuchenkova. Gasanova, ranked World No.241, collected a three-hour and four-minute victory over Katarina Zavatska in the opening round.

The St. Petersburg Ladies Trophy is only Gasanova's second main-draw appearance on the WTA, but she had already shown promising signs this season. In Abu Dhabi in January, Gasanova stunned World No.6 Karolina Pliskova during her WTA main-draw debut week.

Pavlyuchenkova, though, had minimal trouble in the opening set, sweeping through it 6-1 after dropping serve in the opening game. The No.5 seed then twice came back from a break down in the second set, saving a set point at 5-3 in the process before the pair advanced to the tiebreak.

Pavlyuchenkova had three match points in the breaker but Gasanova held firm, slamming strong serves to queue up another set point at 9-8. On that occasion, Gasanova fired a groundstroke on the sideline to force a netted error from Pavlyuchenkova and squeak out the second set.

In the decider, Pavlyuchenkova again fell behind, and faced a match point at 5-4 before swatting it away with a forehand, eventually gritting out a break for 5-5. But, in the decisive third-set tiebreak, it was Gasanova who claimed a 5-2 lead with a backhand winner on the baseline.

Gasanova eased to the victory from there, lining up a clash against fellow Russian and former World No.2 Vera Zvonareva.

In the nightcap, second-seeded Kudermetova was also pushed to the limit before fending off the challenge from qualifier Kamilla Rakhimova, 7-5, 3-6, 7-6(5).

"Of course, I'm really happy about the win today, I think Kamilla played really well today," Kudermetova said. "She fought for every ball and it was a really tough match for me."

This battle was relatively brief for the event -- Kudermetova needed a mere two hours and 53 minutes to eke out the win and make her first quarterfinal since a run to the final at the 2021 season-opening event in Abu Dhabi.

Rakhimova held a point to take a 4-1 lead in the opening set before Kudermetova charged all the way back, collecting the one-set lead with a forehand winner. However, Rakhimova regrouped and notched the last three games of the second set to level the match.

Veronika Kudermetova in action during the second round of the 2021 St. Petersburg Ladies Trophy.

WTA/Jimmie48

With another protracted battle in the offing, Kudermetova took a quick 2-0 lead but was broken back by Rakhimova in the very next game, and there were no more service breaks as the pair moved inexorably into another third-set tiebreak.

In the breaker, five of the last six points went against serve before Kudermetova at last closed out the win after a netted return by Rakhimova.

"I had a little bit more experience, and in the tiebreak I really tried to play more aggressive than before, and I think that was the key," said Kudermetova.

2021 St. Petersburg Highlights: Kasatkina overcomes Sasnovich to make QF