The third-seeded Pegula needed two hours and 20 minutes to overcome Navarro in an all-American quarter-final at Arthur Ashe Stadium on Tuesday, recovering from an early break in the deciding set to complete another impressive comeback at Flushing Meadows.
The victory also extended Pegula's perfect record against Navarro to 5-0, while making her the first woman on the 2026 WTA Tour to reach 50 match wins this season.
Pegula overcomes slow start
Navarro made the stronger start and took the opening set 6-3, putting Pegula under pressure with her aggressive baseline play.
Pegula responded in the second set, raising her level and eventually forcing the match into a deciding set after winning 6-4.
The third set remained closely contested, but Pegula showed greater composure at the crucial moments. She recovered after falling behind early in the set before taking control and sealing a 6-3 victory.
The match featured nine breaks of serve, underlining the difficulty both players experienced in holding their service games during the two-hour, 20-minute contest.
Pegula faces Sabalenka again
Pegula will now meet defending champion and world No. 1 Aryna Sabalenka in the semi-finals on Thursday.
Sabalenka booked her place in the last four earlier by defeating Wimbledon champion Linda Noskova 7-6(1), 3-6, 7-6(7) in another dramatic quarter-final.
The semi-final will be a rematch of their 2024 US Open final, which Sabalenka won, while the Belarusian also defeated Pegula in last year's semi-finals on her way to retaining the title.
For Pegula, the opportunity is another chance to reach her first Grand Slam final and potentially challenge for the world No. 1 ranking. She arrived in New York among the players capable of overtaking Sabalenka at the top of the rankings.
However, the ranking battle could be settled before their semi-final, with second-ranked Elena Rybakina able to move to No. 1 regardless of other results if she defeats Zheng Qinwen in her quarter-final.
Pegula's victory also means the American remains firmly in contention for her first major singles title after reaching the US Open semi-finals for the third year running.