The match lasted one hour and 13 minutes.
The 27-year-old Pole briefly recovered from 0-3 to 3-3 in the first set but ultimately struggled with 29 unforced errors.
It was the third meeting between Fręch and Gauff, with the Polish player losing each encounter decisively.
Despite the loss, this marks Fręch’s first appearance in the third round of the US Open.
Fręch’s exit leaves fellow Pole Iga Świątek as the last remaining Polish woman in the singles draw.
The world's No. 2 tennis player is set to face 29th seed Anna Kalinskaya of Russia in the next round.
Magda Linette was knocked out in the first round.
Meanwhile, also on Saturday, Pole Jan Zieliński and Czech partner Adam Pavlasek defeated Uruguay’s Ariel Behar and Belgium’s Joran Vliegen 7-6 (7-2), 7-6 (7-2) in the first round of the men’s doubles.
(ał)
Source: PAP