Greece's Maria Sakkari triumphed over Russia's Vitalia Diatchenko to advance to the round of 16 on Monday in the St. Petersburg Ladies Trophy in Russia.
World No. 21 Sakkari fought back from a set down to win 3-6, 6-4, 7-6(3) over Diatchenko, winning via a tense final-set tiebreaker.
The Greek 24-year-old was knocked out of the 2020 Australian Open in the round of 16 in Janaury and is yet to win a WTA singles title.
Kazakhstan's Elena Rybakina also advanced through to the next stage in St. Petersburg, defeating Russia's Katerina Siniakova 6-3,6-4.
The pair are joined in the next round by Switzerland's Belinda Bencic, Netherlands' Kiki Bertens, Britian's Johanna Konta and Czech Republic's Petra Kvitova among others.