Novak Djokovic won 12 of the last 14 points on Tuesday to open his title defence at the Paris Masters 7-6(1), 6-4 over French-born American Maxime Cressy.
Djokovic is back on court after last competing in early October when he won Astana.
The sixth-ranked Serb ended after almost one and three-quarter hours with 19 winners and five unforced errors while Cressy hit 26 winners but had 22 unforced errors.
“It was very intense, just a lot of pressure,” Djokovic said.
“When you play someone that serves this well — first and second serve — you don’t have much room to relax and maybe play a softer few games.
“You just have to be on your toes all the time. Credit to him for serving big in some big moments.
I had my chances (in the) first set to break him, second as well.”
The winner added: “A break came at the perfect time actually. I was very pleased with the way I held my serve, didn’t face a break point.”
Djokovic earned his only break of the match in the penultimate game and set up match points a game later with his fourth ace – his opponent fired 15 but also had 10 double-faults.
One point later and the 21-time Grand Slam winner was into the third round after an opening bye.
The Djokovic win was his 24th in a row against American opponents; he has also won his last 10 matches here, a run which includes title runs in 2019 and 2021