Head-to-head: Pegula leads 1-0 Last meeting: Cincinnati Open second round, Pegula won 5-7 6-4 6-2
It is a long-awaited first Grand Slam semi-final for Pegula, who lost her previous six quarter-finals.
She split with long-term coach David Witt after the Australian Open, where she lost in the second round, before her clay season was interrupted by neck and back injuries.
A second-round Wimbledon exit was followed up by a superb run, with Pegula defending her Canadian Open title before reaching the Cincinnati final a week later.
Although she lost the Cincinnati showpiece to Sabalenka, she has been in superb form at her home Slam, having reached the last four without dropping a set.
Born in Buffalo, New York, Pegula’s parents own the Buffalo Bills, who play in the NFL, and they supported her through her junior years as she struggled with injuries.
She claimed a stunning win over Swiatek in the quarter-finals, barely letting up in intensity and returning serve solidly to end her last four hoodoo.
Pegula on Muchova: “She’s so good, so talented, so athletic. I love how she just doesn’t play and comes back and beats everybody. I’m gonna have to bring my best tennis.”
Read More: US Open women’s semi-finals: Aryna Sabalenka faces Emma Navarro and Jessica Pegula plays
