Third-seeded Pegula needed two hours and 20 minutes to get past Navarro on Tuesday, recovering from an early break in the third set of a tense baseline battle on Arthur Ashe Stadium.
“It was really tough,” Pegula said after a match featuring nine breaks of serve. “It was physical, humid. I wasn’t exactly serving my best, and I was fighting a lot of demons out there today.”

Pegula, who has won two titles this year, is among the trio of players who arrived at Flushing Meadows with a chance to supplant Sabalenka atop the world rankings in New York.
Sabalenka beat Pegula in the 2024 final in Flushing Meadows and beat her again in the semis last year on the way to a second crown.
The 32-year-old would have to go all the way to a first major title to have a shot at claiming the top spot.
But the number one issue could be moot by the time Pegula and Sabalenka square-off on Thursday.
Second-ranked Elena Rybakina can seize the top spot regardless of other results with a win over China’s Zheng Qinwen in their quarterfinal on Wednesday.

