Kalinskaya, Pegula completes quarter finals field at Charleston Open

The quarterfinal lineup at the Credit One Charleston Open was completed on Thursday with wins by three of the top four seeds — and one big upset from Anna Kalinskaya over Australian Open champion Madison Keys.

Kalinskaya was a 6-2, 6-4 winner against No. 2 seed Keys in the first match of the night session inside Credit One Stadium, taking advantage of an erratic performance by the World No. 5 to score her first Top 10 victory in 10 months and advance to her second quarterfinal of the season.

Keys hit 40 unforced errors in defeat, won less than 50% of points on her first serve, and converted just one of eight break point opportunities — all of which combined to help Kalinskaya level her all-time head-to-head record against Keys to 1-1.

But Kalinskaya’s win over Keys wasn’t the only upset on paper in the Round of 16. Read on for more top stories from Thursday in Charleston.

“This one is special. I needed this for my confidence. I had an unfortunate start to the year, but it’s nice to be back and playing at such a high level,” she said. “I think the key tonight was to change a little bit the rhythm; I did a few drop shots, especially in the first set.

“I didn’t want to go into very long rallies, because she’s a great player and she has unbelievable strong shots, so I tried to step in on the serve, be aggressive as much as I could, and be very consistent … to keep the level, and I think that was the key.”

Kalinskaya will next face 2020 Australian Open champion Sofia Kenin, who upset No. 5 seed Daria Kastkina in the nightcap, 6-3, 7-6(7).

While her other top seeds have struggled in the first two rounds, there has been no such dram for No. 1 seed Pegula. After losing three games in her first round, Pegula lost just five against Ajla Tomljanovic to book a spot in her fifth quarterfinal of the season, 6-3, 6-2.

The match was a far cry from the 6-1, 4-6, 6-3 semifinal that the two played in Austin last month, with Pegula winning five straight games in the middle of the match to pull away.

She’ll take a perfect 6-0 head-to-head record against her next opponent, defending champion Danielle Collins, into the quarterfinals. Collins came from a break down in both sets to defeat No. 11 seed Jelena Ostapenko 7-5, 6-3 and win her eighth straight match in Charleston.

Zheng survives, Alexandrova tops Shnaider: Olympic champion Zheng Qinwen’s 13th consecutive clay-court win, meanwhile, didn’t come as easily. The No. 3 seed was forced to come from a break down in the final set en route to defeating No. 13 seed Elise Mertens, 6-3, 3-6, 6-3.

She will next face No. 9 seed Ekaterina Alexandrova, who was a 6-1, 6-2 winner against No. 6 seed Diana Shnaider. Linz champion Alexandrova’s two wins this week snapped a four-match skid — which followed eight consecutive wins — dating back to the semifinals of the Qatar Total Open in February.