AVONDALE, Ariz. — A hectic week for the No. 24 Hendrick Motorsports team culminates Sunday in a repeat appearance in the NASCAR Cup Series Championship 4.

The Round of 8 finale at Martinsville Speedway one week ago left the 26-year-old leaning on his Chevrolet in agonizing anticipation, awaiting a review of the legality of Christopher Bell’s last-lap wall ride to determine which of the two would advance to the title bout. Bell was penalized, leading Byron back to the title quartet.

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Days removed from the anxious wait on pit road, Byron still shivers thinking back to those Martinsville moments.

“It was excruciating,” Byron said in Thursday’s Championship Media Day availabilities. “I felt like it was so long. I was honestly numb to whatever was going to happen. I was honestly just preparing for not being in, then thinking about I felt like we did all we could do. It is what it is at this point.

“It was a lot of waiting. I felt like the longer I waited in some ways that it wasn’t going to work out. But yeah, it did.”

With his advancement comes attempt No. 2 to win Cup title No. 1. Byron won three of the year’s first eight races and none since. But Byron’s unsteady summer has been rectified by an outstanding postseason performance, in which the No. 24 Chevy has compiled six consecutive top-six finishes.

The unity within the walls of Hendrick Motorsports — a company celebrating its 40th anniversary — has brought the group surrounding the No. 24 car closer.

“I haven’t ever felt as bonded to my team as I am now,” Byron said. “We had a meeting on Sunday night about it. I feel like we’ve turned the page really, really quickly. For me personally, I’ve blocked out a ton of the noise. I haven’t looked at social media. I don’t really care. I’m just focused on trying to get the 24 car as fast as I can.

“I think past experiences have probably helped fuel that where I’ve been through enough BS in my Cup career where I know what to focus on and what to block out.”

Proving himself is nothing new to Byron, whose entire racing career started via the computer simulation on iRacing. His resume since then has done plenty to state he deserves to be here: Rookie of the Year honors after a record season in the NASCAR Craftsman Truck Series in 2016; an Xfinity Series title as a rookie; Cup Series Rookie of the Year one year later. Since 2020, Byron is a 13-time winner at the sport’s top level. Unsteady no longer, Byron now seems unflappable.

“That’s how my career started, was always having to prove something,” Byron said. “No one ever felt like I was supposed to be in a race car, so… From day one, it’s always been that motivation for me. Then this year’s no different because of the nature of, yeah, not winning yet in the playoffs.

“We’re still waiting to peak. That’s a good feeling.”

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In a year so special to team owner Rick Hendrick and Hendrick Motorsports, the NASCAR Cup Series’ winningest organization, Byron has already furthered his name in the legendary team’s history books. He opened the year returning the storied No. 24 Chevrolet to Victory Lane in the “Great American Race” with a Daytona 500 triumph then scored a sentimental win just seven races later at Martinsville Speedway, where Hendrick donned its cars in ruby red and had hundreds in attendance to celebrate its 40-year milestone.

“I feel like our team has just been through a lot of big moments,” Byron said. “Like, no bigger than the 500 this year, lining up on the front row with a shot to win that race. I feel like those moments really prepare you for moments like this weekend. And moments like Martinsville, just kind of putting yourself in those pressure situations.

“There was no more pressure than the 40th anniversary race at Martinsville in the spring. Just feel like those moments definitely prepare us.”

Byron, the first Daytona 500 champion to reach the Championship 4 since Denny Hamlin in 2020, can bookend the season with victories and stands as the only Hendrick driver in the Championship 4 — with all hands on deck from the four-car organization to help prepare his Chevrolet for Phoenix.

“We have worked super closely on the setup this week with all the other teammates we have at HMS,” Byron said. “That’s one thing, just the hands on the car. We don’t have the dilemma of what Penske has where we’re trying to prepare two cars. It’s all focused on the 24. I feel like there were a lot of hands on deck this week at the shop, which is really cool to see. Then we’ll have simulation going on back at the shop all the way up till the green flag. I think that’s what’s different, is just the fact that we don’t have really any other focus but this race.

“Yeah, it’s cool (to have all focus on the 24). I didn’t expect that. Yeah, it shows the teamwork at HMS, kind of what Mr. H and everyone there has built for that to be the case. We all race hard. I feel like at the end of the day, we always want the best for one another.”

In Friday’s 50-minute practice session at Phoenix, Byron posted the fourth-quickest lap at 132.004 mph, his 27.272-second lap time just 0.098 seconds shy of fellow Champ 4 contender Ryan Blaney’s fastest lap. Blaney was quickest across 15-lap averages ahead of Hamlin and Byron, with Blaney’s Team Penske teammate Joey Logano just behind Byron. Tyler Reddick, who won at Homestead-Miami Speedway to advance to his Championship 4 debut, was 11th of the 24 drivers who posted a run of 15 consecutive laps and ran the 21st-fastest lap in Friday’s session.