Jenson Button has revealed he came close to fainting during his NASCAR Cup Series debut due to the heat generated inside his Ford Mustang.

The 2009 F1 champion managed to finish 18th at the end of what proved to be a 75-lap Echopark Automotive Grand Prix at the Circuit of the Americas in Austin, Texas, as the event ran for an extended seven laps due to a green-and-white chequered finish.

Button, however, nearly never saw the conclusion.

“I finished 18th after almost stopping because I had heat exhaustion,” said Button. “It was so hot.

“I don’t have a fan in my seat, which really didn’t help me too much, and I thought I was going to faint in the car, so I stopped twice for a minute.

“They put ice on me, gave me loads of water, and I went back out. I was so close to getting out of the car because I thought I was going to faint. I must’ve drank eight, nine bottles of water during the race.

“The team kept me calm, and it’s the reason why we got a good result in the end. So, I was happy.”

Button – “I got it wrong every time”

After qualifying 24th in the 39-car field, two places behind fellow F1 champion Kimi Raikkonen, the race proved to be what Button described as “an emotional rollercoaster”.

“At first, it was terrible,” reflected Button. “I mean, I must’ve been last by the end of it (the start), and I was just like, ‘Everyone, go. I just need to drive and find a rhythm.’

“I’ve never gone through a corner two wide, so often, and trying to place my car in the right place, I just got it wrong every time.

“Normally, if you’re a little bit slow through a corner, nobody tries to overtake you from the outside because they’re not going to make it all the way on the next one.

“But here they do, because they get a wheel inside for the next one, and if you turn in, you turn around.

“The first stint was really bad. It was embarrassing for me. I was like, ‘Alright guys, we need to pit, freshen the tyres and I need some air. I need some fresh air.’

“I got that. The pace was good, consistency was good. I was really happy, and I passed a few cars, which was nice.

“We got a little bit unlucky with the safety car because it was just two laps before our window. Pitted, then the next stint was mayhem.

“We also made a couple of changes that just didn’t work. Big oversteer – went from the car feeling great to really difficult to drive.”

Mustang “wasn’t quite right after Raikkonen collision

Button also collided with Raikkonen at one stage in driving his #15 Rick Ware Racing Mustang which further undermined his race.

“I had a massive whack from Kimi, and it fell off after that,” added Button. “The car wasn’t quite right. Every time I turned in, the rear tyres would chatter, then immediately to oversteer.

“It was really difficult, but toward the end, we made some good calls stopping and putting on fresh tyres.

“I enjoyed the last three restarts. I got good placement and good overtaking moves from the outside.”

Including the three restarts, there were eight caution periods overall, accounting for 17 laps of a race won by Tyler Reddick by 1.411s to Kyle Busch, who now trails championship leader Ross Chastain by 19 points.

Button is due to compete in two additional NASCAR races this year – the Grant Park 220 on July 2 on the streets of downtown Chicago, and the Verizon 200 on August 13 on the road course at Indianapolis Motor Speedway.

In addition to his NASCAR races, the 43-year-old will also contest in this year’s 24 Hours of Le Mans in a Next Gen Chevrolet Camaro ZL1 with two-time Le Mans winner Mike Rockenfeller, and seven-time NASCAR Cup champion Jimmie Johnson.