The United Autosports driver added a second LMP2 triumph at Le Mans, having previously been victorious in 2017, in the ORECA-Gibson 07 he shared with race rookies, IndyCar driver Nolan Siegel and IMSA SportsCar Championship competitor Bijoy Garg.
Their #22 machine was one of six main LMP2 crews that was in contention during the contest, which featured treacherous conditions for much of the 24 hours, including a four-hour period during the night when torrential rain forced the drivers to run behind a safety car.
"The track was just changing every lap," Jarvis told Autosport. "It was dry and then it would rain and you were on slicks. It was cold and you can't get tyre temperature.
"I must've nearly crashed the car 10 times - you're literally hanging on to it."
Jarvis - who has also finished on the overall Le Mans podium three times with Audi - tackled some of the hardest conditions of the race, including a nerve-wracking final stint in which he had started to build a lead but still had a moment at the chicane.
"You are always a small mistake away from putting it in the wall so I was relieved to see the chequered flag," he added, having eventually triumphed by just under 20 seconds over the #34 Inter Europol ORECA.
"There were times where I wasn't sure if we were going to win in it or stick it in the wall."
Jarvis also paid tribute to his United Autosports squad for its strategy during the race and his inexperienced team-mates, saying: "They came out here as rookies and they're leaving as winners."
Siegel also admitted to being "so happy" that Jarvis - contesting his 13th Le Mans - took over from him for the final two hours and preferred "stressing out on the sidelines than stressing out in the car".
Garg added that Saturday night's wet weather was the first time he had driven in the rain in the dark.
"I was definitely thinking, 'why do I have to learn it here?'" he told Autosport.
"But glad to have done it, stayed on track and maintained good track position throughout."
