Raducanu, who declined the opportunity to represent Great Britain at the Olympics, triumphed 7-6 (8-6) 6-2 over the 51st-ranked Stearns.
Raducanu served to secure the opening set just as a torrential downpour began. She won the set in a tie-break after a delay.
“It’s challenging when you get rained off at such a significant point today. The dynamics of the game may be impacted,” Raducanu remarked.
She will play the victor of Paula Badosa, the wildcard, and Liudmila Samsonova, the third seed.
Raducanu praised the audience for being patient throughout the late-night game on Wednesday.
I anticipated that the match against Peyton would be difficult, particularly because Stearns was playing at home,” the woman continued. “The past few months have gone well for me, and I believe I’m gaining some traction.
The world number 89 declined the offer to compete in the Olympics because she did not want to return to playing on clay at Roland Garros. She is still working on her comeback following surgery on her wrist and ankle. Instead, she is giving hard courts more importance than the upcoming US Open, which she qualified for and won in 2021.
