Coco Gauff has reached her first US Open final by defeating Karolina Muchova 6-4 7-5, in a match interrupted for 50 minutes by environmental activists including one who glued his bare feet to the floor at Arthur Ashe Stadium.
Dreams of an all-American final were dashed, though, when Australian Open champion Aryna Sabalenka recovered from losing the first set to love to beat 17th seed Madison Keys 0-6 7-6 (7-1) 7-6 (10-5).
The toughest part for Gauff might have been closing out the victory: she needed six match points to get it done, raucously supported by a partisan crowd that chair umpire Alison Hughes repeatedly implored to quieten down.
After failing to convert one match point while serving for the win at 5-3, then another four in what turned out to be the last game, Gauff smacked a forehand winner to cap a 40-stroke exchange that was the longest of the contest. Muchova then missed a backhand to end it.
"I grew up watching this tournament so much, so it means a lot to be in the final. A lot to celebrate, but the job is not done," said 19-year-old Gauff, the first American teenager to make it to the title match in New York since Serena Williams in 2001.
Gauff was up by a set and 1-0 in the second when three protesters disrupted play from seats in an upper level of the arena.
Two of them were escorted away relatively quickly but it took more time to remove the person glued to the ground.
The victory was the 11th in a row for Gauff and the 17th in her past 18 matches, a run that began after a first-round exit at Wimbledon in July.
Second seed Sabalenka, who is guaranteed to move up to No.1 in the rankings for the first time next week, looked to be on her way out of the tournament but recovered to win an epic showdown.
Having won the first set 6-0, Keys went 4-2 up in the second and served for the match at 5-4, only for Sabalenka to break her to love and begin the comeback.
"You just have to keep trying, keep staying there, and keep pushing it," Sabalenka said.
"Lucky me, somehow magically, I don't know how, I was able to turn around this game."
The Belarusian dominated the tie-break and the pair exchanged breaks in the third before it headed to the inevitable deciding breaker.
When Sabalenka got to 7-3 ahead she thought she had won the match, forgetting it was now first to 10, and dropped her racket in delight.
She managed to refocus, though, and wrapped up the victory in two-and-a-half hours.
"She played incredible tennis, another level," Sabalenka said of Keys.
"I kept reminding myself that I lost a lot of tough matches. I mean, one day all those matches should just, like, help me somehow."
While Sabalenka was delighted, Keys was understandably distraught.
"Everyone at the start of the tournament would be really, really excited to be in the semis," the world No.17 said, breaking into tears.
"Right now it sucks. But being able to take this and turn it to a positive is really possible."