Martina Navratilova has slammed the climate protestors who disrupted the US Open semi-final clash between Coco Gauff and Karolina Muchova.

Sixth seed Gauff and tenth seed Muchova were vying for a spot in the final of the New York major. The American had won the first set 6-4 and was 1-0 up in the second when three climate activists in the crowd stood up and started yelling "End fossil fuels!"

Two of the protestors were removed from the building, but the third had glued their bare feet to the floor, meaning that it took a while for officials to get them out of the building. As a result, the match was delayed by 49 minutes and the players returned to the locker room.

In a statement released after the incident, the United States Tennis Association (USTA) said:

"Following the first game of the second set in the Gauff-Muchova match, play was halted due to a protest conducted by four spectators. Three of the four protesters were escorted out of the stadium without further incident. The fourth protester affixed their bare feet to the floor of the seating bowl.

"Due to the nature of this action, NYPD and medical personnel were needed in order to safely remove this individual from the stadium. The four protesters were taken into NYPD custody. In total, 49 minutes elapsed before play resumed."

The 59-time major champion Navratilova responded to the post on X, formerly known as Twitter, by suggesting that the people's choice of protest was not an effective one.

"Not the best way to garner support," the 66-year-old wrote.

After play resumed, Gauff went on to win the match in straight sets 6-4, 7-5. She will face second seed Aryna Sabalenka in the final of the US Open.