The second-seeded Frenchman achieved the feat in the fourth game of the first set in Sunday's final in Marseille, going on to beat Serb Medjedovic 7-6 (7-4) 6-4 to successfully defend his title at the indoor hard-court event.
The 26-year-old left-hander was rock-solid on serve throughout, hitting 13 aces overall with no double-faults and winning 82 per cent of his first-serve points.
It was Humbert's seventh career title in his ninth final, and got him back on the title trail in his homeland after finishing runner-up to Alexander Zverev at the Paris Masters in November.
"It wasn't easy because he played really, really good, but I'm super happy to have my title back," said Humbert.
"I'm so proud of it, maybe the best because I was a little bit stressed at the beginning of the tournament. With a title to defend, it was not easy to manage, but I'm super proud of it.
"It means a lot to me because it's in France. It's so nice to be back in Marseille. I love to play here. The fans were so good, they gave me the energy to win all four matches, so thanks to them."
In Buenos Aires, 18-year-old Joao Fonseca defeated fifth seed Francisco Cerundolo 6-4 7-6 (7-1) to become the youngest South American to win a title in the ATP Tour era (since 1990).
Competing in his first tour-level final, Fonseca twice unsuccessfully served for the match but regrouped to sink a fourth Argentine of the week amid a raucous atmosphere in the capital.
"Unbelievable week, even in Argentina there are some Brazilians cheering for me," Fonseca said.
"I want to thank my family, my friends and my sponsors for just helping me achieve my dream, which is to play tennis. Of course I want to be No.1, of course I want to win slams, titles, but my dream is just to play tennis, and I'm living it."
One year ago, Fonseca was No.648 in the rankings. He has begun 2025 on a high, winning an ATP Challenger Tour title, upsetting Andrey Rublev as a qualifier at the Australian Open, and now claiming his first ATP Tour trophy.
With his 105-minute victory, the reigning Next Gen ATP Finals champion will climb to a career-high No.68 on Monday.
28°C