In a clash of big servers, it was the American number one who came out on top, sending down 16 aces against a misfiring Kyrgios who hit just seven and offset most of those with six double faults.
The 11th-seeded Fritz needed just 51 minutes to condemn Australian Kyrgios to his second defeat since losing to Novak Djokovic in the Wimbledon final.
Such was Fritz's domination on serve that Kyrgios could not muster a single break opportunity the entire match while the American converted three of his seven chances.
"It feels great to have my game come together today," said Fritz. "That’s the kind of match I really needed to give me a lot of confidence going into the next match, going to the US Open, a lot of things are clicking for sure."
Fritz will next meet Russian sixth seed Andrey Rublev who ground out a 6-7(7) 7-6(3) 6-2 win over Italy's Fabio Fognini.
Fourth-seeded Greek Stefanos Tsitsipas sailed into the third round with a business like 6-3 6-4 victory over Serbian Filip Krajinovic while eighth-seeded Pole Hubert Hurkacz, runner-up in Montreal on Sunday, lost to his doubles partner this week, big-hitting American John Isner, 7-6(5) 6-7(5) 6-2.
It was a good day for Canada with both seventh seed Felix Auger-Aliassime and Denis Shapovalov picking up victories.
Auger-Aliassime cruised past Australian Alex de Minaur 6-3 6-2 while Shapovalov rallied for 3-6 6-4 6-3 win over in-form American Tommy Paul to register back-to-back victories for the first time since May.
In an all-British clash, ninth seed Cameron Norrie fought back to beat former world number one Andy Murray 3-6 6-3 6-4.
