Liudmila Samsonova won a late-night clash at the Citi Open, knocking out No.2 seed and reigning US Open champion Emma Raducanu 7-6(6), 6-1 to reach the semifinals in Washington, D.C.
World No.60 Samsonova earned the second Top 10 win of her career with her 1-hour and 46-minute victory over Raducanu, the 10th-ranked player in the world. Samsonova's previous Top 10 win came earlier this year when she upset then-No.7 Karolina Pliskova in Stuttgart.
Samsonova saved four set points in the first set — two at 5-4 and two in the tiebreak — on her way to gritting out the one-set lead. After prevailing in the closely-contested opener, Samsonova cruised through the second set to reach her second semifinal of the year, after Stuttgart.
In a match that started late Friday and ended after midnight on Saturday, big-hitting Samsonova had 33 winners, nine of which were aces. Raducanu could only muster up eight winners and came unglued with 24 unforced errors in the encounter.
In Friday's other quarterfinal matches:
(LL) Wang Xiyu def. (4) Victoria Azarenka 6-1, 6-3: The 21-year-old Chinese lucky loser Wang made the second WTA semifinal of her career, ousting former World No.1 Azarenka in 80 minutes. Wang's run through the main draw continues despite falling in the final round of qualifying.
Azarenka won a grueling 80-minute set earlier on Friday as part of a straight-sets win over Tereza Martincova in a rain-delayed second-rounder.
But two-time Grand Slam champion Azarenka could not rebound for her second match of the day, taking a medical time-out at the start of the second set before succumbing to the left-hander. World No.95 Wang converted six of her 11 break points and will face Samsonova in the semis.
Daria Saville def. (Q) Rebecca Marino 6-1, 7-5: Former Top 20 player Saville ended the run of Canadian qualifier Marino, who had defeated former Top 10 players Venus Williams and Andrea Petkovic back to back this week.
World No.88 Saville, who fell to No.627 in February of this year after Achilles tendon surgery in 2021, backed up her upset of No.1 seed and defending champion Jessica Pegula.
Marino fought back from a 6-1, 3-0 deficit at the rain delay, but Saville held on and moves into her first tour-level semifinal since 2018 Acapulco.
(6) Kaia Kanepi def. Anna Kalinskaya 6-7(4), 6-4, 6-3: Kanepi, a quarterfinalist at this year's Australian Open, made her first semifinal of the season with a grueling two-and-a-half hour victory over Kalinskaya, in the only match that finished before Friday's rain delay.
"It was a very tough match," former Top 20 player Kanepi said afterward. "It was so hot on the court. ... I don't know actually how I managed to win. Just tried to play my game, but she also played her game really well."
Kanepi will face Saville in the semifinals.