The four-time Grand Slam champion from Japan needed only 72 minutes to eliminate ninth-seeded Jabeur and collect her fifth triumph this year over a player ranked in the top 20 in her return from maternity leave.
Osaka has won all seven of her WTA titles on hardcourts, including the 2018 and 2020 US Opens and 2019 and 2021 Australian Open crowns, and hopes to add this US Open hardcourt tuneup to the list.
"Everyone knows I really love hard courts. I wasn't thinking too much. It was very instinctual," Osaka said of her victory. "When I play the best players, like Ons, I tend to play better.
"I'm feeling quite confident in myself as a person and as a player, and I think that showed a little."
Osaka took her first triumph in Canada since reaching the 2019 quarter-finals with 14 winners and 13 unforced errors while Jabeur made 27 unforced errors in her first match since Wimbledon.
Next in Osaka's path is Belgium's Elise Mertens, with whom she has split two matches this year. Mertens won at Indian Wells. Osaka won on grass at 's-Hertogenbosch in the Netherlands.
Washington Open winner Paula Badosa of Spain eliminated Denmark's Clara Tauson 6-1, 6-4, stretching her win streak to five matches and setting up a second-round match with fourth seed Jelena Ostapenko.
Olympic doubles silver medalist Diana Shnaider, the 14th seed from Russia, was down a break three times in the final set before rallying past Britain's Harriet Dart 6-3, 3-6, 7-6 (7/2).
China's Yuan Yue ousted Spain's Cristina Bucsa 6-3, 6-3 to reach a second-round match against second seed Aryna Sabalenka, the two-time and reigning Australian Open champion.
