The quarterfinal matches at the Credit One Charleston Open are set after Thursday`s games. Victories came from three of the top four seeded players, alongside a significant upset by Anna Kalinskaya against Madison Keys, the Australian Open champion.
Anna Kalinskaya defeated No. 2 seed Madison Keys with a score of 6-2, 6-4. This match, the first of the night session at Credit One Stadium, saw Kalinskaya capitalize on an uncharacteristically error-prone performance from Keys, who is ranked No. 5 globally. This win marks Kalinskaya`s first victory against a Top 10 player in ten months and propels her into her second quarterfinal of the season. Keys struggled with 40 unforced errors, won less than half of her first serve points, and only converted one out of eight breakpoint opportunities. These factors contributed to Kalinskaya evening their head-to-head record at 1-1.
However, Kalinskaya`s triumph over Keys was not the only unexpected result in the Round of 16. More key stories from Thursday in Charleston are detailed below.
Kalinskaya `Needed This` Amidst a Difficult Start: Kalinskaya, who reached a career-high ranking of No. 11 last October following a strong 2024 season including a WTA 1000 final in Dubai and WTA 500 final in Berlin, hadn`t replicated that form in the initial months of 2025. After missing the Australian Open due to illness, she arrived in Charleston with a 4-7 season record and had only achieved back-to-back wins in one tournament in February in Singapore, where she withdrew from the semifinals due to injury.
Following her 11th career Top 10 victory against Keys, the 26-year-old Kalinskaya expressed that this win was something she “needed”.
`This victory is particularly meaningful. I needed it for my confidence. My year began poorly, so it feels great to be performing at such a high level again,` she stated. `The key tonight was varying the rhythm a bit; I used a few drop shots, especially in the first set.`
`I wanted to avoid extended rallies because Madison is an excellent player with incredibly powerful shots. I tried to be assertive on my serve, aggressive whenever possible, and maintain consistency… to sustain my level of play, which I believe was crucial.`
Kalinskaya`s next opponent will be Sofia Kenin, the 2020 Australian Open champion, who also caused an upset by defeating No. 5 seed Daria Kasatkina in the evening`s final match, 6-3, 7-6(7).
Pegula Maintains Dominance: While other top seeds have faced challenges in the early rounds, No. 1 seed Jessica Pegula has shown consistent strength. After conceding only three games in her opening match, Pegula allowed just five games to Ajla Tomljanovic, securing her place in her fifth quarterfinal of the season with a 6-3, 6-2 victory.
This match was significantly different from their semifinal clash in Austin last month, which Pegula won 6-1, 4-6, 6-3. In this encounter, Pegula won five consecutive games mid-match to take control.
Pegula will face defending champion Danielle Collins in the quarterfinals, holding a perfect 6-0 head-to-head record against her. Collins overcame a break deficit in both sets to defeat No. 11 seed Jelena Ostapenko 7-5, 6-3, marking her eighth consecutive win in Charleston.
Zheng Advances, Alexandrova Overcomes Shnaider: Olympic champion Zheng Qinwen`s 13th successive clay-court victory was not easily achieved. The No. 3 seed had to recover from a break down in the final set to defeat No. 13 seed Elise Mertens, 6-3, 3-6, 6-3.
Her next match is against No. 9 seed Ekaterina Alexandrova, who defeated No. 6 seed Diana Shnaider 6-1, 6-2. Alexandrova, the Linz champion, ended a four-match losing streak with her two wins this week, following a previous streak of eight consecutive wins that ended after the Qatar Total Open semifinals in February.
