NEW YORK -- The US Open semifinal between Coco Gauff and Karolina Muchova was delayed by 49 minutes because of a disruption by four environmental activists in the Arthur Ashe Stadium stands Thursday night. One protester glued his bare feet to the concrete floor.
Gauff was leading 1-0 in the second set when play was halted. She would go on to win 6-4, 7-5.
Security guards and, later, more than a half-dozen police officers went over to confront the protesters, who were wearing shirts that read, "End Fossil Fuels." The U.S. Tennis Association said three of the protesters were escorted out of the stadium without further incident, but it took longer to remove the person who stuck his feet to the ground.
The USTA added that NYPD and medical personnel were needed in order to safely remove that person. All four activists were taken into police custody.
"It was a bit challenging, because, you know, it's not like a typical delay," Gauff said. "So we didn't know how long it was going to take. We were talking to the supervisor and security. You know, they could say it could be as quick as five minutes or as long as an hour. It was tough to figure out if we stay warm or conserve energy.
Gauff added: "But, you know, it's life. It happens. So I just try my best to keep the momentum that I had going from winning the first set and the first game."
Muchova said that, initially, she "thought it was, like, fans screaming, cheering."
Spectators were asked to move away to clear a path for the police, who were cheered by fans sitting near the section where the disruption happened.
One protestor said the group wanted the US Open to be accountable because it has sponsors who are large corporations whose policies are contributing to global warming.
"I always speak about preaching about what you feel and what you believe in," Gauff said. "It was done in a peaceful way, so I can't get too mad at it. 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."
Gauff sat on her sideline bench for a bit during the break in the match, eating fruit out of a plastic container, before hitting a few practice serves. Muchova was briefly visited by an athletic trainer during the interruption.
Later, both players headed toward the locker room as the delay continued. Gauff sat on a treadmill, a towel draped over her lap, while chatting with members of her team.
Said Muchova: "I just wanted to get off the court and then keep myself little warmed up and not just to stand there."
It is the latest in a recent series of protests at sporting events -- and tennis, in particular -- related to the use of fossil fuels.
At Wimbledon in July, two matches were interrupted when environmental activists jumped out of the stands at Court 18 and scattered orange confetti on the grass.
At a US Open tuneup tournament in Washington, D.C., last month, about a dozen people were asked to leave the site after chanting and displaying signs protesting the use of fossil fuels.
"I had a feeling it was going to happen this tournament," Gauff said. "It happened in the French Open, it happened in Wimbledon. So, you know, following the trend, it was definitely going to happen here. I just was hoping it wasn't in my match, and honestly I thought we made it through.
"But it is what it is. I think that, you know, the moments like this, yeah, are history-defining moments. Like I said, 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."
Gauff, a 19-year-old American, and Muchova, a 27-year-old from the Czech Republic, were both playing in the semifinals at Flushing Meadows for the first time.
Their match was the first of the evening. The other women's semifinal, between Aryna Sabalenka of Belarus and Madison Keys of the United States, began shortly after Gauff's victory, with Sabalenka winning in three sets.
Gauff and Sabalenka will play for the women's singles championship in Ashe on Saturday.
Information from The Associated Press was used in this report.