The Frenchman, who has slipped to 33 in the world rankings after a series of injuries, offered fans plenty of jaw-dropping moments with his trademark acrobatics and baseline winners.
The charismatic 32-year-old, watched by Ukrainian girlfriend Elina Svitolina - seventh in the women's rankings - eased through the first set after breaking Troicki in the fourth game.
US Open
US Open Order of Play Day 4 - Raducanu, Djokovic, Barty in action
02/09/2021 AT 09:12
Troicki, who reached the final in 2016, put up more of a fight in the second but Monfils clinched the set with a superb service game to take his perfect record against the Serb to 5–0.
The seventh-seeded Monfils served nine aces to wildcard Troicki’s eight, although the Frenchman also served eight double faults during a match which was over in just under an hour.
"I think my rate of service was not very good," said Monfils. "I need to serve better if I want to stay in the tournament."
Next up for Monfils is the winner of the first-round clash between Serbian Laslo Djere and Kazakhstan's Mikhail Kukushkin.
Big-serving Daniel Brands stunned Georgian fifth seed Nikoloz Basilashvili 7-6(7) 7-5 while fellow German qualifier Yannick Maden beat Adrian Mannarino of France 6-4 7-6(4).
Tokyo 2020
The honeymoon can wait - Newlywed Svitolina focuses on Olympics
21/07/2021 AT 09:47
'Go crazy!' - Monfils reveals his Playlist with plenty of singing
03/06/2021 AT 20:35