At the end of a much more fierce fight of two and a half hours, Nick Kyrgios, winner of the Washington tournament in 2019 and finalist of the last Wimbledon, came to the end 6-7 (5/7), 7-6 (14/ 12), 6-2 from stage regional Frances Tiafoe (27th).
A high-intensity meeting, removed and offering beautiful points which ended up turning in favor of the Australian, always so whimsical - evidenced by his kicks between the legs - and grumpy, against himself or the public considered too much talkative between exchanges.
But, relying on his formidable serve (35 aces), he knew how to keep his cool to save five match points in the decisive game of the second set.
Tiafoe, frustrated at not having been able to complete the match on these occasions, then lost his footing, leaving Kyrgios to escape after passing very close to the exit.
The latter will face Mikael Ymer on Saturday, who defeated American Sebastian Korda (54th) 6-2, 5-7, 6-3.
Two wins in one day for Rublev
Later, Andrey Rublev had less trouble dismissing another American, JJ Wolf (99th in the world).
8th in the world and seeded N.1, the Russian qualified for the semi-finals of the Washington hard court tournament on Friday, winning in two sets (6-2, 6-3).
He will face for a place in the final the Japanese Yoshihito Nishioka (96th), won 7-6 (7/5), 4-6, 7-5 of the marathon having opposed him to the Briton Daniel Evans (40th), after 3h35 of struggle.
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Rublev is looking for a 4th title this year, after those won in Marseille, Dubai and Belgrade.
Such a performance would make him the most successful player this season along with Rafael Nadal and Carlos Alcaraz.
The 24-year-old, realistic failing to be impressive at the start of the day to dismiss the American Maxime Cressy (32nd) 6-4, 7-6 (10/8), in the quarter-finals disputed 24 hours late because of the storms that had hit the capital of the United States the day before, was much more convincing against Wolf.
He took the American's serve four times without ever conceding his own, despite four opposing opportunities.
Aggressive and controlling the game as he pleases, he won without flinching in 1h20.
Raducanu eliminated
Among the women, Liudmila Samsonova (60th) and Xiyu Wang (95th) created the surprises of the day, eliminating Victoria Azarenka (20th) and Emma Raducanu (10th) respectively.
The Russian was more solid than the Briton, who will have the heavy task of defending her title at the US Open in three weeks, winning 7-6 (8/6), 6-1.
The Chinese took advantage of the physical failure of the Belarusian to win their duel 6-1, 6-3.
They will compete for a place in the final.
The other poster of the last four will pit the Estonian Kaia Kanepi (37th), who beat 6-7 (4/7), 6-4, 6-3 the Russian Anna Kalinskaya (71st), at the Australian Daria Saville (88th), who won 6-1, 7-5 against Canadian Rebecca Marino (111th), from qualifying.