Catherine, Duchess of Cambridge, Emma Raducanu

Kate Middleton; Emma Raducanu

| Credit: Karwai Tang/WireImage; AELTC/David Gray - Pool/Getty

British teen tennis phenom Emma Raducanu has a big fan among top royals! Kate Middleton shared the joy of tennis fans in the U.K. by applauding the 18-year-old's terrific semifinal win as she prepares for the final on Saturday.