The Saturday broadcast of the women's final peaked at 3.4 million viewers while the men's final, which saw Medvedev win his first major title, had a peak of 2.7 million the following day, ESPN said.
The women's title clash between the teenagers -- the first major final in the Open era to feature two unseeded players -- had an average of 2.44 million viewers, a 37 percent increase over the 2020 final when Naomi Osaka beat Victoria Azarenka.
A day after British 18-year-old Raducanu became the game's first qualifier to win a major, men's world number one Djokovic took the Arthur Ashe Stadium court against second-ranked Medvedev in the men's final.
A win for the Serb would have made him the first man in 52 years to win all four majors in the same year and give him a 21st Grand Slam to move ahead of Roger Federer and Rafa Nadal.
The final on Sunday afternoon, which typically faces stiff competition for viewers from the first week of the NFL season, averaged 2.05 million viewers, up 37 percent from last year.
The 2021 edition of the hardcourt major averaged 881,000 viewers in US prime time, a 33 percent jump over last year and a 13 percent increase for the two weeks of broadcast, ESPN said.
Channel 4, which signed a last-minute deal with UK rights holder Amazon Prime to broadcast the match free to air, saw their broadcast peak at 9.2 million viewers during Raducanu's improbable win.