Byron entered the elimination race with a 30-point buffer, but he quickly saw his points cushion evaporate.
Ryan Blaney scored 19 out of a possible 20 stage points, while Byron scored zero. He remained mired back in the pack, struggling to get a handle on his No. 24 Hendrick Motorsports Chevrolet.
He ended up finishing 13th, one lap down, but that was just enough. He advanced by just eight points over Denny Hamlin.
"Obviously we were not very good," Byron said post-race. "Our worst race of the year. These guys deserve it so much. They work so hard. Honestly, probably with 50 to go I felt really, really bad. I just had did drive the hell out of it. The guys stuck with me, they kept motivating me through little bits and pieces, just kind of keeping my mind straight.
"I'm just really thankful for them. It was just, yeah, a slugfest. Everyone raced me there good at the end. Congrats to Ryan [Blaney]. I was really happy for him, brother-in-law. He was really fast. But, man, we just had to hang on. Just had to dig a little bit deeper.
"I knew when I got out of the car I was just beat. But the result means more than anything. These guys work so hard. We've worked so hard all season. I'm just really proud of them. "
Byron will be part of the Championship 4 for the first time in his career. His best points result until now was sixth in 2022.
He will now face his Hendrick Motorsports team-mate Kyle Larson, as well as Joe Gibbs Racing's Christopher Bell and Team Penske's Ryan Blaney in the title-decider at Phoenix Raceway.
The most recent winner of a Cup Series race at Phoenix? Well, that happens to be Byron, who won there in March of this year. Blaney finished second, Larson fourth, and Bell sixth.
