NEW YORK, NEW YORK - AUGUST 26: Karolina Muchova of Czechia serves with partner Jakub Mensik of Czechia (not pictured) during the Mixed Doubles Semifinal of the US Open against Mirra Andreeva and Andrey Rublev at USTA Billie Jean King National Tennis Center on August 26, 2026 in New York City. (Photo by Caleb Bowlin/Getty Images)

NEW YORK, NEW YORK - AUGUST 26: Andrey Rublev and Mirra Andreeva react after a point during the Mixed Doubles Semifinal of the US Open against Karolina Muchova of Czechia and Jakub Mensik of Czechia at USTA Billie Jean King National Tennis Center on August 26, 2026 in New York City. (Photo by Caleb Bowlin/Getty Images)

NEW YORK, NEW YORK - AUGUST 26: Andrey Rublev and Mirra Andreeva react after a point during the Mixed Doubles Semifinal of the US Open against Karolina Muchova of Czechia and Jakub Mensik of Czechia at USTA Billie Jean King National Tennis Center on August 26, 2026 in New York City. (Photo by Caleb Bowlin/Getty Images)

NEW YORK, NEW YORK - AUGUST 26: Karolina Muchova of Czechia and Jakub Mensik of Czechia interact during the Mixed Doubles Semifinal of the US Open against Mirra Andreeva and Andrey Rublev at USTA Billie Jean King National Tennis Center on August 26, 2026 in New York City. (Photo by Caleb Bowlin/Getty Images)

NEW YORK, NEW YORK - AUGUST 26: Karolina Muchova of Czechia returns a shot with partner Jakub Mensik of Czechia during the Mixed Doubles Semifinal of the US Open against Mirra Andreeva and Andrey Rublev at USTA Billie Jean King National Tennis Center on August 26, 2026 in New York City. (Photo by Caleb Bowlin/Getty Images)

Czech Republic's Jakub Mensik and Czech Republic's Karolina Muchova celebrate a point during the mixed doubles final tennis match against Switzerland's Belinda Bencic and Italy's Flavio Cobolli of the 2026 US Open tennis tournament at the USTA Billie Jean King National Tennis Center in New York on August 26, 2026. (Photo by TIMOTHY A. CLARY / AFP via Getty Images)

Czech Republic's Karolina Muchova serves while playing with partner Czech Republic's Jakub Mensik during the mixed doubles final tennis match against Switzerland's Belinda Bencic and Italy's Flavio Cobolli of the 2026 US Open tennis tournament at the USTA Billie Jean King National Tennis Center in New York on August 26, 2026. (Photo by CHARLY TRIBALLEAU / AFP via Getty Images)

Czech Republic's Karolina Muchova serves while playing with partner Czech Republic's Jakub Mensik during the mixed doubles final tennis match against Switzerland's Belinda Bencic and Italy's Flavio Cobolli of the 2026 US Open tennis tournament at the USTA Billie Jean King National Tennis Center in New York on August 26, 2026. (Photo by CHARLY TRIBALLEAU / AFP via Getty Images)