But Sinner soon quashed those dreams, breaking back as Fritz attempted to serve for the set and doing the same two games later to wrap up the win after two hours and 16 minutes.
It was more straightforward in New York as he rarely looked troubled by Fritz, who struggled to build any momentum.
"I know we have been waiting for a champion for a long time so I'm sorry I couldn't get it done this time," said Fritz.
Sinner said the title "meant so much because the last period of my career was not easy" before he became tearful and dedicated the victory to his aunt.
"He's stepped up a role and I feel like he's taking everything as seriously as he can and fair play to him, that shows he wants to stay."
He subsequently parted ways with the physio and his fitness trainer - but questions continued about whether Sinner's case had been handled differently to those of other players because of his world number one status.
But he has seemingly been able to put the controversy behind him, manoeuvring his way through tough tests against Britain's Jack Draper and 2021 champion Medvedev.
Tom Hanks stars in an intense thriller based on true events. VideoTom Hanks stars in an intense thriller based on true events
However, Sinner then underlined his status as world number one, upping the ante when it mattered most to strike the crucial blow as Fritz served to stay in the set at 5-4 down.
It comes just 19 days after it was revealed he had been cleared of any wrongdoing after twice testing positive for a banned substance in March.
Get the Sport Report every Thursday to stay up to speed with everything you need to know in the world of sport. Get the newsletter
It has been nearly 50 years since a man won their first and second Grand Slam titles in the same season, and Sinner is now a long way clear of the rest at the top of the rankings.
Além da possibilidade por existir um convidado todas as 米兰体育 semanas e da base dos programas ser em estúdio, está em aberto de que alguns se realizem num ambiente exterior e em multiplos localidades do país.
Cheered on by a home crowd packed with celebrities and sporting stars, Fritz got off to a shaky start when he dropped serve in the first game.