Kyle Larson is now a two-time NASCAR Cup Series champion, but the Hendrick Motorsports star admits luck played a key factor at Phoenix on Sunday afternoon.

Joe Gibbs Racing rival Denny Hamlin had the fastest car and led for 208 of the 312 racing laps at Phoenix Raceway, and looked set to finally put his championship hoodoo to bed, cruising to the black and white checkered flag.

With four laps to go, Hamlin was seconds clear of William Byron in second when disaster struck for the No. 11. A tire blowout for William Byron brought out a caution, sending the race to overtime in a season-defining moment.

Under the caution, Kyle Larson - who appeared to be down and out at one stage - and his crew chief made the strategy call of a lifetime, opting for only two tires, which gave him track position over Hamlin, who opted for four.

Crucially, however, several other drivers opted for the two-tire strategy, meaning that whilst Larson came out of pit road in fifth, Hamlin was down in 11th.

Ultimately, even on four tires, it proved too much work to do for Hamlin in two laps, eventually finishing sixth, three spots behind Larson, whose third place was enough to secure his second Cup Series crown.

Larson speechless after championship win

Larson's win certainly fell somewhat into his lap, as brilliantly as he drove in overtime, and post-race, the Hendrick Motorsports star admitted that his team had not had a strong car on the day.

“Honestly, I can’t believe it,” Larson said. “Like, we didn’t lead a lap today. Somehow won the championship. I mean, really, I’m just speechless. I can’t believe it. We had an average car at best.

“We had the right-front go down (earlier), lost a lap,” Larson added. “Got saved by the caution. Did the wave-around. Was really bad that run. We took two tires. I was like, 'Oh, God, here we go. We’re going to go to the back now.’

“It had a lot more grip than I anticipated.

Larson: We got lucky

Larson continued: "We got lucky with the final caution. I was really hoping we were going to take two again. I felt like I learned a lot on that restart, bombing (Turns) 1 and 2 really hard. Thought I could do the same thing if we got another one.

“Just unbelievable. What a year by this Hendrick Motorsports (crew). Cliff Daniels, everybody, his leadership, his complete leadership just showed that whole race. Keeping us all motivated. Always having a plan. All of that. That’s just the story of our season.

“Again, just unbelievable. I cannot believe it. This is insane!”