Fifth-seeded Konta entered the Australian Open tuneup tournament after losing her last four matches in 2017, including a first-round exit at the U.S. Open.
After dropping the first set, Konta hit form quickly and had decisive service breaks early in the second and third sets before clinching it on her second match point, breaking Keys' serve to finish off in just over two hours.
"To get the chance to play such a high-quality match so early on is only a good thing to me," Konta said. "And to be able to come through in a three-set match as well and to get that much court time, it's a good thing."
Keys, playing just her second match since her career-best run at the U.S. Open, had 11 aces and hit 37 winners but made 38 unforced errors in humid conditions on Pat Rafter Arena.
"It was good tennis today — I haven't played a match in four months, so it's like a win for me," Keys said. I "Played really well. She played better. I'm not that upset about it."
In other matches, third-seeded Elina Svitolina opened with a 6-2, 6-4 win over Carla Suarez Navarro and 2012 champion Kaia Kanepi beat Daria Kasatkina 6-2, 6-2. Two seeded players went out in the first round, with Lesia Tsurenko beating No. 8 Ashleigh Barty 6-3, 6-2 in a night match and qualifier Aliaksandra Sasnovich ousting No. 6 Kristina Mladenovic 1-6, 6-3, 7-5.
Two-time Wimbledon champion Petra Kvitova withdrew from the tournament earlier Monday because of a viral illness and was replaced in the draw by Heather Watson, who lost 6-0, 6-3 to Anett Kontaveit.
On the men's side, No. 8-seeded Mischa Zverev held off Australian qualifier John-Patrick Smith 6-4, 7-5, Ryan Harrison beat Leonardo Mayer 6-4, 3-6, 6-2, Horacio Zeballos had a 6-3, 6-4 win over Ernesto Escobedo and Jared Donaldson beat Jordan Thompson 6-2, 6-4.