Thanasi Kokkinakis has overcome French star Gael Monfils to set up an Atlanta Open second-round clash with fellow Australian Alex de Minaur, the two-time and defending champion.

Kokkinakis came from 4-0 down in the deciding set tiebreaker to win 6-1 3-6 7-6 (7-5) on Monday, securing his first tour-level victory since reaching third round of the French Open.

"In a tiebreak you can go down quickly and can come back quickly. I got a point on his serve and then two on mine and all of a sudden he's feeling the pressure," Kokkinakis told atptour.com.

"It was pretty stressful, especially in the first set, which wasn't much fun. He posed a lot of challenges and he is one of the quickest players on tour. I can't get a ball by him most of the time."

Now he faces second seed de Minaur, who won this tournament in both 2019 and 2022.

"Demon and I are good mates. We share Davis Cup together, we train a little bit together," Kokkinakis said.

"He's a hell of a player and he's leading the way for us Aussies. He's the defending champion here in Atlanta so he obviously likes the conditions.

"I know it won't be easy. I practised with him the other day and he gave me a spanking. It should be a fun match."

Fellow Australian Aleksandar Vukic also advanced to the second round, beating American wildcard Ethan Quinn 7-6 (7-5) 6-3, but countryman James Duckworth went down to South African qualifier Lloyd Harris 3-6 6-3 6-2.