Coco Gauff maintained her composure following a nearly hour-long disruption caused by climate activists as the American teenager sailed into the US Open final with a straight-sets win over Karolina Muchova.
Gauff has now become the youngest American woman to reach the US Open final since Serena Williams in 1999.
The teenager broke Muchova twice early on to race into a 5-1 lead. But her Czech opponent fought back with powerful groundstrokes.
Muchova cut Gauff's lead to 5-4 after the teenager had twice served for the set. However Muchova faltered when her return landed in the net as Gauff broke back.
One game into the second set, activists disrupted proceedings, forcing a 49-minute stoppage.
The USTA said three of the four protesters were escorted out of the stadium without incident but a fourth "affixed their bare feet to the floor of the seating bowl".
It is not the first time a major tennis tournament has been disrupted by protesters.
At Wimbledon this year Just Stop Oil activists caused two matches, one involving Britain's Katie Boulter, to be suspended after running onto the court throwing jigsaw pieces and confetti.
Last year's French Open semi-final between Casper Ruud and Marin Cilic also had to be halted after a woman tied herself to the net.
Following resumption, both players seemed relatively unfazed. Muchova double-faulted to help Gauff break in the eighth game but saved match point in the next game before breaking the American’s serve.
Muchova saved four more match points in the 12th game but Gauff would not be denied, surviving a 40-shot rally on the penultimate point with a forehand winner for a 6-4, 7-5 victory.
Gauff thus cemented her status as a future star of the game, showing great composure under pressure.
After the match, she admitted the protesters did break her concentration but sympahised with the protesters.
"I definitely, I believe, you know, in climate change," Gauff was quoted as saying by AFP. "I think there are things we can do better.
"I know the tournaments are doing things to do better for the environment. Would I prefer it not happening in my match? 100 per cent, yeah. I'm not gonna sit here and lie.
"I think that moments like this are history-defining moments. I prefer it not to happen in my match but I wasn't pissed at the protesters. I know the stadium was because it just interrupted entertainment.
"Obviously I don't want it to happen when I'm winning up 6-4, 1-0, and I wanted the momentum to keep going. But hey, if that's what they felt they needed to do to get their voices heard, I can't really get upset at it."
Meanwhile, Aryna Sabalenka came from a set and a break down to deny the US Open crowd an all-American final with a thrilling win over Madison Keys.
The second seed lost the first set to love against Keys, but hit back to win 0-6, 7-6 (1), 10-5 and book a Saturday showdown with Gauff.
Keys looked in a hurry as she raced through the first set in just 30 minutes.
The 17th seed 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 a grand comeback.
The Belarusian dominated the tie-break and the pair exchanged breaks in the third before heading towards a 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.