2019 champion Madison Keys and 2017 champion Daria Kasatkina will square off in a quarterfinal showdown at the Credit One Charleston Open on Friday, following victories in the Round of 16 on Thursday.

No.9 seed Keys of the United States battled past No.8 seed Magda Linette of Poland 6-2, 3-6, 6-1 in the late match on Thursday night. Keys took a hair over two hours to grab her third win in four meetings with this year's Australian Open semifinalist Linette.

Keys continued her strong run of success in Charleston, notching her 20th career match-win at the tournament. Along with hoisting the trophy in 2019, Keys was also a finalist in 2015 and a semifinalist in 2018.

Back-to-back forehand winners gave Keys the one-set lead, but Linette was the sturdier player in the second set. The Pole saved all three break points she faced in the second set to level the match.

However, Keys got the early break for 2-0 in the decider, then survived a break point in a lengthy five-deuce game to consolidate for 3-0. Keys held on from there, and she finished the match with 36 winners, tripling Linette's 12.

No.3 seed Kasatkina had a quicker time booking her quarterfinal spot, with a 6-3, 7-6(3) victory over American Bernarda Pera earlier on Thursday. Kasatkina needed 1 hour and 32 minutes to subdue 38th-ranked Pera in their first meeting.

After reaching the Adelaide International 2 final in January, Kasatkina failed to pick up many victories in the rest of the hardcourt season, winning only three of her next nine matches.

But the World No.8 is getting back on track on the green clay of Charleston, where she won her first Hologic WTA Tour singles title six years ago at the age of 19.

Pera, who won her first two WTA singles titles last year, came back from a break down in the second set, saving two match points at 5-4 en route to forcing a tiebreak. But Kasatkina won five straight points in the breaker to take a commanding 5-1 lead, and she closed out the win from there.

Keys has an overwhelming 8-1 win-loss record against Kasatkina. Last year at Melbourne Summer Set 2, Kasatkina finally got her first win over Keys in her eighth try, but Keys won their most recent clash in San Diego at the end of last season.