“Of course I’m happy… It’s unbelievable for me and my family.
“But I still have some work to do in New York this year and I will think about becoming No. 1 after the US Open.”
Sabalenka will now face another Grand Slam clash with Keys after defeating the American in the quarter-finals of Wimbledon in July.
Keys, who reached the US Open final in 2017, defeated Wimbledon champion Marketa Vondrousova of Czech Republic 6-1, 6-4 to reach the last four.
Vondrousova was frustrated by her failure to convert any of her nine break points, while Keys was perfect on three of her three.
Keys said, “I love playing in front of the home crowd here – you never feel like you can’t get out of any situation.”
Vondrousova said she struggled to deal with the power of Keys’ serves and groundstrokes.
Vondrousova said, “I felt like I was under a lot of pressure from the very first point.” “There wasn’t much to do, to be honest. It was very tough. I was just trying to fight, trying to run for every ball. She was very good.”
The match was stopped in the first game of the opening set after a spectator required emergency medical treatment. US Open organizers later stated that the incident was not related to the heat.