Nick Kyrgios is out of the US Open after eventually being out-battled by Russia's Karen Khachanov in a tense quarter-final in New York.
The 27-year-old Australian, who needed treatment on his left thigh after the first set, lost 7-5 4-6 7-5 6-7 (3-7) 6-4 to 27th seed Khachanov.
Khachanov is into his first major semi-final after edging the bigger points.
The 26-year-old plays Norwegian fifth seed Casper Ruud, who beat 13th seed Matteo Berrettini 6-1 6-4 7-6 (7-4).
Rafael Nadal's exit in the last 16 against American Frances Tiafoe on Monday means a first-time Grand Slam men's singles champion will be crowned in New York on Sunday.