William Byron badly wanted out of his Hendrick Motorsports Chevrolet late Sunday at Martinsville Speedway, needing to escape the heat that was so bad it hurt his vision. But with a shot at competing for the NASCAR Cup Series championship on the line, Byron gutted it out and finished 13th — which he called his worst race of the season. It was enough, however, to advance him into the championship race by eight points.

“It means a lot,” Byron said. “I’m sure I’m going to go home and really think about it. I’m happy for Ryan [Blaney], he deserved (the win). They were really fast today. I’m really happy for my team, I can’t state that enough.

“With 50, 60 to go, it was so blurry inside the car and I just wanted to pull in but you’re not going to do that. I was going to have a failure or do something first. So, just really proud of the team. They gave me the opportunity. This is my dream. I love to race cars, I didn’t grow up doing it, but I love what I do and they believe in me.”

In addition to the unusually high temperature for a fall Martinsville race (it was in the 80s), Byron struggled to keep his head cool when the helmet fan didn’t work. An issue that has cropped up more than once for him at Martinsville, and Byron couldn’t get his helmet off quick enough upon climbing from his car and needing to sit down.

“It was a really hard-fought battle,” Byron said. “I’m just super thankful for my team. My crew chief, Rudy [Fugle], just knew what buttons to push to keep me in the game. We’ve had so many tough times together and when he took over the 24 car, he believed in me and gave me all the tools I needed to go out and have success. I’m just really thankful for him and the whole team – all the guys on the team believe in me and we did all we could, and they deserved it.

“We had a great season. It would have sucked to not make it, so we dug in.”

Byron didn’t earn any stage points Sunday after qualifying 16th. And the car did not handle well once the race started, Byron struggling in traffic, saying he had nothing for the competition, and ran outside the top 15 much of the afternoon. Where he finished was about the highest Byron ran under green flag conditions.

“It was kind of (expletive) in a bottle,” Byron said. “I’ve never been so mad in a race car, I’ve never wanted to get out so much, I’ve never been so frustrated at the car and how loose I was, how tight I was in spots. I just had no grip. It’s tough to do that. But a lot of people raced me with respect; I appreciate that. I feel like we do that and vice versa, and a lot of people took care of me. I’m just really thankful for that.

“We just really deserve it. We deserve to go to Phoenix. It’s nice to see it pay off.”

Entering the weekend, Byron had a 30-point advantage on the cutline. But when qualifying didn’t go well, it turned the outlook for race day and gave Byron a bad feeling.

“It was pretty awful,” Byron said of the weekend. “I was optimistic we had the car in practice, we were kind of OK on averages. The car was loose in, tight center, not what you’d really want, but I was just hopeful the track was going to come to us or something, and when we qualified the way we did, I was like, ‘Oh no.’ I was so nervous sleeping last night. I don’t think I said a word to (girlfriend) Erin on the way here in the car. Just so nervous. I had that feeling in my stomach.

“It’s nothing against all the work we put in, but I didn’t have the feeling in the car that I wanted. I knew it was going to be a battle. But when you get in those battles, I think you underestimate how tough it’s really going to be, and when you’re running 21st or whatever, it’s not fun back there. It was really tough.”

In his fifth postseason appearance, the second time he’s made the Round of 8, Byron succeeds at advancing to the title race. Byron leads the series with six victories and 20 top-10 finishes, and he entered the postseason as the No. 1 seed.

“I saw a lot of guys and they were pretty whooped and when I saw him and he’s in great shape, you could tell today was really hard on him,” Jeff Gordon said of Byron. “All those long green-flag runs, but also, the car just wasn’t handling well, so he had to fight the steering wheel as well as the heat. And the stress, too that goes along with trying to make it into Phoenix. So, I’m really proud.

“I’m proud of what they’ve done all year long that they get to enjoy what this next week — get this behind them – but go enjoy this week has to offer because whether you win the championship or not, it’s just super cool to be a part of the experience, and I feel like they’ve really worked hard to earn that this year. I honestly think they have a great shot at it, too.”