DAYTONA BEACH, Florida — In constant rain that ended up stopping the race early, NTT IndyCar Series rookie Colton Herta was victorious Sunday in the GT Le Mans class in his IMSA WeatherTech SportsCar Series debut in the No. 25 BMW M8 GTE for BMW Team RLL at the Rolex 24 at Daytona.

The 18-year-old (at right in above photo) co-drove the winning entry with Philipp Eng, former Indy Pro 2000 driver Conor De Phillippi and late substitution Augusto Farfus. Herta set the fastest lap of the race in GTLM during an overnight stint in his first-ever GT race.

“I’m happy, super happy,” Herta said after the 24-hour marathon that was stopped twice by red flags for treacherously wet conditions and halted for good 10 minutes before its scheduled conclusion. “I did not expect this out of my first GT race, just kind of a wave of perfect events and we came out on top.

Herta won six races over the past two seasons in Indy Lights presented by Cooper Tires, as he prepared to ascend to the NTT IndyCar Series, where he made his debut in the 2018 season finale and finished 20th. He’ll embark on a full season in 2019 with Harding Steinbrenner Racing and enter with a major professional win under his belt.

“This is the biggest race I’ve ever won and it’s such a cool one to win,” Herta said of the Rolex 24. “Obviously maybe not 100 percent the way we wanted to win, but a win is a win and I’ll take it.”

Herta recalled the dicey conditions on the Daytona International Speedway road course as similar to a 2017 Indy Lights race at Watkins Glen in a rainstorm. Herta did have flashbacks to that race while he was driving in the downpour.

“This was way worse (than 2017),” he said. “This was so much more rain, aquaplaning all over the place. Luckily, I was only in the car when they went green down the front straight and then there was a massive crash, but it was just too wet at that point.

“It was crazy, I got to a quarter throttle down the front straight and made it into third gear. Usually, (I’m) entering in sixth gear, 180 mph. I was going third gear probably around 100, 120 mph.”

Colton’s father, Bryan Herta, was ecstatic for his son. After Bryan Herta’s cars finished fifth and ninth in the TCR class during Friday’s four-hour Michelin Pilot Challenge race, the 1993 Indy Lights champion was able to take off his team owner hat and follow his son’s progress in the difficult conditions.

“You always worry because that’s the nature of it, right? You have no control so all you can do is worry,” said Bryan Herta, co-owner of the No. 98 Honda to be driven by Marco Andretti this year in the NTT IndyCar Series. “But this was just such a huge opportunity for him to be part of this program with BMW RLL, and you know this was just a chance for him to grow and learn to continue to evolve as a race car driver. To win the race was more than you could really dare to dream, so I’m just very happy for him.”

BMW Team RLL co-owner Bobby Rahal has now employed both Hertas as drivers: Bryan in Indy cars from 1996-99 and Colton for the Rolex 24. Rahal sees similarities in the father and son.

“They’re very similar, they even sound alike,” said Rahal. “Colton’s got a lot of talent, so I’m sure this won’t be his last Daytona 24 Hours.”

Rahal’s NTT IndyCar Series team will field Graham Rahal and Takuma Sato again this season, which kicks off with the Firestone Grand Prix of St. Petersburg on March 10. Herta will compete at St. Pete as well before resuming his BMW sports car duties at the Mobil 1 Twelve Hours of Sebring presented by Advance Auto Parts on March 16.