When Bryan Herta was 18 years old, he was attending the Skip Barber Driving School and hoping to make a career out of driving race cars. Fast forward 30 years to Sunday afternoon at the Circuit of The Americas where Herta watched his 18-year-old son do the unthinkable: win an IndyCar race in only his third start.

“It’s amazing, hard to comprehend at this minute, but I am so proud of him,” said the former IndyCar winner who now co-owns Marco Andretti’s car. “I know he’s got potential and promise, but you just don’t expect that so quickly.”

In becoming the youngest victor in IndyCar history, Herta displayed the maturity and moxie of a 28-year-old veteran. He qualified fourth on Saturday in his Harding Steinbrenner Honda despite missing a practice period after losing an engine. He snatched third in the opening lap and held his position all afternoon until a fortuitous yellow flag put him in the catbird seat with 14 laps to go.

Will Power (Team Penske Chevrolet) had dominated to that point, but he and second-placed Alex Rossi (Andretti Racing Honda) hadn’t pitted when that caution waved and they were toast.

That left young Herta in the lead but it was hardly comfortable since Penske’s Josef Newgarden was right behind him on the restart. The 2017 IndyCar champion had three times more push-to-pass so Colton looked like a sitting duck.

But the skinny kid who looks 15 pounced like a sage of speed on the restart and pulled away to almost a four-second advantage before easing up at the checkered flag.

“I was calling Marco’s race so that kept me occupied and I didn’t know exactly what was going on with Colton. But that would have probably made me more nervous,” said the proud pop. “To hold off Josef under those circumstances was pretty impressive.”

No, for a team that wobbled into 2019 with a shaky portfolio and still has no title sponsor led by a teenager making his third start, this was beyond impressive. Mike Harding and George Michael Steinbrenner got the best of Roger Penske — comparable to the old Kansas City Athletics beating Mantle, Maris and the Bronx Bombers in the ’60s.

“Everything had to work out perfectly and we needed a little luck, but Colton was awesome,” said Steinbrenner, grandson of the late New York Yankees owner who backed Herta in Lights. “Our pit stops were good, we knew we had to stay ahead of Newgarden on all three stops and we did. It’s just surreal.”

Harding, the Indianapolis pavement contractor who in January intended to run two cars (the other for Pato O’Ward until things fell apart, with O’Ward let out of his contract), has a technical partnership with pal Michael Andretti that’s elevated his little team to rarified air.

Now he owns the fairytale story of the season, so finally finding a sponsor should be easier.

“We’ve got a lot of people out looking and this should help,” said Harding.

Yet the reality of what happened at COTA can’t be dismissed as a fluke or luck.

Colton, the second version of Hertamania, has been quick since slapping on a skateboard at age 4. He won in karts, Formula Fords and Indy Lights, and he possesses a calm demeanor that belies his age.

“I think the two years he spent in Europe by himself really helped his maturity,” said Bryan. “My wife and I didn’t go with him, he didn’t know anyone, so his only friends were the mechanics on his car. Hanging out with them, asking questions and being in that environment helped him immensely.”

That scenario — and driving for Trevor Carlin in British Formula 4 when he was 15-16 — also helped Colton develop some chassis savvy.

“His ability to understand the car and read it and communicate with his engineer is amazing,” said Brian Barnhart, the Steinbrenner Harding president who worked with Al Unser Jr. back in his mechanic days. “He’s so detailed and analytical, and he’s just a kid. It blows me away.”

Partnered with engineer Nathan O’Rourke, the younger Herta has obviously found some instant chemistry. In two races he’s been among the fastest drivers and has not put a wheel wrong while dueling with IndyCar’s finest.

It was fitting that Colton put on a cowboy hat in victory lane because there just might be a new sheriff in town.

Standing under the podium and snapping photos of this memorable moment in racing history, it was easy to be happy for Bryan Herta. One of the nicest, most gracious and honest people in the IndyCar paddock — and one who was also a pretty damn good racer — Herta Sr. is not the boastful type and stayed out of the victory photos because it was Colton’s celebration.

Yet even he couldn’t resist a little bragging.

“I think he’s getting the hang of it,” Bryan said with a grin.