New York, New York - American tennis star Coco Gauff shrugged off a 49-minute stoppage caused by climate protesters to power into the US Open final on Thursday with a straight sets defeat of Karolina Muchova.

The 19-year-old from Florida advanced to her first final at Flushing Meadows after winning 6-4, 7-5 in a semi-final that took nearly three hours to complete due to disruption by protesters.

Gauff will face second seed Aryna Sabalenka of Belarus in Saturday's final.

Gauff later admitted the long delay had been "challenging" but said she had sympathy with the activists and their cause.

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"I definitely, I believe, you know, in climate change," Gauff said. "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%, 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."

Muchova meanwhile suggested little could be done to stop protests in future.

"I mean, it happened at Wimbledon, as well. We see it here and there on some occasions," she said. "It is what it is. I mean, it's obviously changed the rhythm a little bit. What can we do about it? People."

Gauff will be targeting her first Grand Slam title after battling to victory on the Arthur Ashe Stadium court.

Gauff, who is now the youngest American woman to reach the US Open final since her idol Serena Williams in 1999, had looked to be cruising towards victory in the first set.

The teenager broke Muchova twice early on to race into a 5-1 lead, but her Czech opponent regained her composure and turned the tables as the fluency returned to her powerful groundstrokes.

Muchova fought back to break, cutting Gauff's lead to 5-4 after the teenager had twice served for the set.

But Muchova then faltered, and Gauff broke back to clinch the first set when her rival hammered a backhand return into the net.

The second set was only one game old when environmental activists disrupted play, chanting "End fossil fuels." One of the protesters glued themselves to the floor of the stands, forcing a 49-minute stoppage.

When the players returned, a tense second set unfolded.

Muchova held off a match point in the 10th game to level at 5-5 before Gauff held for a 6-5 lead.

Muchova then saved four more match points on her serve before finally succumbing on the sixth match point, hammering a backhand return long to leave Gauff victorious.

Muchova said she had felt off her game from the opening point.

"Today I was not feeling it from the start until the end," she said. "I'm pretty sad about the outcome, that I didn't put the best out of me on the court."