Australia's 19-year-old Alex De Minaur saved four match points Saturday and advanced to Sunday's ATP Washington Open final, where he will face third-ranked defending champion Alexander Zverev.
The Aussie teen outlasted 20-year-old Russian Andrey Rublev 5-7, 7-6 (8/6), 6-4 after two hours and 52 minutes while 21-year-old German Zverev ousted Greek teen Stefanos Tsitsipas 6-2, 6-4.
"It's one of the biggest wins of my career," De Minaur said. "Dug deep and never gave up. Couldn't be prouder of myself."
De Minaur, ranked 72nd, won the last six points of the tie-breaker to force a third set, then broke the 46th-ranked Rublev in the final game, winning on his fourth match-point chance when the Russian double-faulted.
It will be the youngest combined age of any ATP final since 20-year-old Rafael Nadal beat 19-year-old Novak Djokovic in 2007 at Indian Wells after the ATP's first all-21-or-under semi-finals since 1995 in Buenos Aires.
"This is amazing for tennis," Zverev said. "It's good to see the young guns come up."
Zverev seeks his ninth career ATP title and third of the year after Munich and Madrid. He could join a Washington back-to-back champions list that includes Argentina's Juan Martin del Potro (2008-09) and Americans Andre Agassi (1990-91 and 1998-99) and Michael Chang (1996-97).
"I'm playing great and hopefully I can win," Zverev said. "I hope I get out there and play a good match and get to Toronto with another title."
It's only the second career ATP final for De Minaur, the son of a Spanish mother and Uruguayan father.
In the companion WTA event, two-time Grand Slam champion Svetlana Kuznetsova of Russia won 6-2, 6-2 twice to reach the final, first downing Kazakh eighth seed Yulia Putintseva in a match that had been halted by rain then dispatching Germany's Andrea Petkovic.
World number 128 Kuznetsova, the 2004 US Open and 2009 French Open champion, will play for the title Sunday against 44th-ranked Croatian Donna Vekic, who eliminated China's 85th-ranked Zheng Saisai 7-5, 6-3.
Fognini topples Del Potro
Italian Fabio Fognini captured his first career hardcourt title on Saturday, surprising Juan Martin del Potro 6-4, 6-2, in the final of the ATP Los Cabos Open.
It is the 31-year-old Fognini's eighth ATP Tour victory but his first on hardcourts after previously winning only on clay.
The win helps validate a career-best season for Fognini as this is his third title of 2018 to go with wins in Sao Paulo and Bastad.
Buzarnescu in final
Fifth-seeded Mihaela Buzarnescu will be gunning for her first WTA title when she takes on Maria Sakkari in the final at San Jose, California.
Romania's Buzarnescu, ranked 24th in the world, rallied to beat fourth-seeded Belgian Elise Mertens 4-6, 6-3, 6-1.
Greece's Sakkari, ranked 49th in the world, will also be chasing a first career title on Sunday.
She rallied from a set and two breaks down to beat American Danielle Collins 3-6, 7-5, 6-2.
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