On a humid Tuesday at Arthur Ashe Stadium, Jessica Pegula outlasted Emma Navarro in a fractured, serve-breaking quarterfinal to earn her third consecutive US Open semifinal — and her third consecutive meeting with Aryna Sabalenka, the woman who has twice denied her at this stage. At thirty-two, Pegula arrives not merely as a competitor but as someone chasing a first Grand Slam title against the very opponent who has made it most difficult, while the world number one ranking itself hangs in the atmospheric tension of an unplayed match.