Russian duo Svetlana Kuznetsova and Vera Zvonareva recorded contrasting victories on home soil to reach the last eight of the St. Petersburg Ladies Trophy.  

Kuznetsova - who has won both the French and US Open during her distinguished career - needed just over an hour to get past teenage qualifier Wang Xinyu by a 6-1 7-5 scoreline.  

The 35-year-old converted six of the nine break-point opportunities she created, though was made to work for her win in the second set having previously taken nine of the opening 10 games.  

After failing to serve out for the match when 5-3 ahead, the fourth seed eventually prevailed when recording a break of her own with the score at 6-5.  

Zvonareva, meanwhile, was on court for three hours and 10 minutes as she produced an impressive upset, knocking out third seed Fiona Ferro 6-7 (8-6) 7-5 7-6 (7-2).  

"We both were fighting for every point, trying to hang in there. I think I was able to play some good tennis when it mattered, and I'm happy with the win of course,” Zvonareva said after being involved in the longest match in the history of the tournament, per the WTA's website.  

The 36-year-old came out on top in a deciding tie-break having been unable to hold on to an early 2-0 lead in the set.  

Anastasia Gasanova and Katarina Zavatska had set a new record for the longest contest earlier on Wednesday, the former eventually prevailing 6-2 6-7 (8-6), 7-5 after three hours and four minutes in an eventful first-round tie.

Ekaterina Alexandrova is another Russian player to progress to the last eight, seeing off Tereza Martincova in straight sets.

In the final match, Romanian qualifier Jaqueline Cristian surprised Jelena Ostapenko 6-3 7-6 (11-9) to reach her first ever WTA 500 quarter-final, where her opponent will be Kuznetsova.