Tunisian Jabeur has come within touching distance of Grand Slam glory in the past, reaching the last two Wimbledon finals and the 2022 US Open title clash but she has not been able to cross the finish line.
A third-round meeting with fellow former Flushing Meadows runner-up Fernandez represented a tricky challenge and the pair exchanged breaks midway through the opening set before Jabeur took control of the contest on serve.
With limited success when she peppered the Suzanne Lenglen surface with her trademark drop shots against quick-moving 31st seed Fernandez, Jabeur quickly found herself trailing 3-1 in the second set.
"Everybody knows Leylah, she plays very well. She's a very aggressive player," said Jabeur. "I knew that I had to finish the match before the third set and I won some points at the right moments.
"It was a bit tough on serve but I'm very happy to win."
Jabeur, a quarter-finalist here last year, took the next two games to go level, before saving a set point in a five-deuce game and eventually completed the victory with an ice-cool show in the tie break.
Up next for Jabeur is unseeded Dane Clara Tauson, who stunned former runner-up Sofia Kenin 6-2 7-5.