Coco Gauff reached her first US Open final by defeating Karolina Muchova 6-4 7-5 in a match interrupted for 50 minutes by environmental activists. One of the protesters glued his bare feet to the concrete in the Arthur Ashe Stadium stands Thursday night. Gauff will face Aryna Sabalenka, who defeated 2017 runner-up Madison Keys 0-6 7-6(1) 7-6(5), in the final on Saturday.