For the 10th time in NASCAR's 75-year history, the Cup Series championship will be determined by a winner-take-all season finale that will see the highest finisher among the Championship 4 drivers win the Cup title. And at the end of NASCAR's diamond anniversary season, those four all represent something very significant.

The Championship 4 of Kyle Larson, Christopher Bell, Ryan Blaney and William Byron marks the youngest Championship 4 in the history of the NASCAR playoffs, as the drivers will have a combined age of 28 years, 11 months and 25 days old when they take the green flag Sunday at Phoenix Raceway. After many years of trying to reach this point while serving as part of the sport's supporting cast -- namely to grizzled veteran drivers with 10 or more years of experience and some gray in their beards -- each of the Championship 4 now steps into the spotlight on one of NASCAR's biggest stages for the right to go into the record books as the 2023 Cup champion.

Prior to the beginning of on-track activity on Friday, each of the Championship 4 drivers met with the media Thursday to discuss their seasons, circumstances and chances of winning the Cup championship at Phoenix. Here are some of the notable storylines that emerged from Championship 4 Media Day.

Race of ages

The youngest Championship 4 in NASCAR history is competing for the Cup Series title on a weekend representing more than just the maturation of NASCAR's youth movement. Sunday will mark 47-year-old Kevin Harvick's final Cup start before retirement, bringing an end to the career of NASCAR's longest-tenured driver and a future Hall of Famer. 

The next to the plate among NASCAR's elder statesmen -- 43-year-old Martin Truex Jr. and 42-year-old Denny Hamlin -- were both eliminated from the playoffs in the Round of 8. Kyle Busch, still a somewhat spry 38 years old but set to become the longest-tenured driver in Cup having raced full-time since 2005, was eliminated from the playoffs in the Round of 12.

In a certain sense, this Championship 4 means NASCAR's new generation has finally arrived at the top of the sport. Back in 2018, when Byron was a rookie in Cup, Blaney went from the Wood Brothers to Penske and other young stars got their shot in Cup as well. NASCAR's promotion of their young stars was met in kind by Harvick, Truex and Busch dominating the season -- reminding everyone that, as Harvick put it, "Old guys rule."

"When I came into the Cup Series it was the old versus new, and the old guys ruled with Harvick and Jimmie [Johnson]," Byron recalled. "Those guys were dominating races. It was kind of a joke ... that NASCAR promoted us [young drivers] so much. People were laughing at it.

"We're here now. It's cool. It's all the guys I grew up racing against."

None of the Championship 4 can be called old -- not even Larson, who is only 31 despite being in his 10th year as a Cup driver. But neither come into the Championship 4 as total greenhorns either; most have grown to the point where they have now assumed leadership roles both within their race teams and the Cup garage as they now set the standard for even younger drivers.

"I personally feel like one of the older guys now with [Austin] Cindric and [Harrison] Burton being on my team, them being like 21, 22. Makes me feel old," Blaney said. "But, no, it's just neat to see all different kinds of ages, right? You see such a wide variety throughout the years of the Final 4 of guys with tons of years under their belts, guys with only a handful of years. 

"All that kind of culminates, and this is just one of those ones that everybody is in the middle of their career. William is younger, but he's been around for a long time. It's one of those things. I'm not going to say it's turning of the tide 'cause it's not, because there's still a lot of great racers that are still in their upper 30s. It's just one of those weird Championship 4s that everyone seems to be around their late 20s."

All in the (extended) family

Having made the Championship 4 for the first time in their respective careers, William Byron and Ryan Blaney will be pitted against each other as they both try to win their first Cup championship. But it's more than just a battle between two contemporaries in NASCAR's youth movement -- it's also a fight between two who have basically become brothers-in-law.

Ryan Blaney's sister, Erin, is William Byron's longtime girlfriend -- which creates a dynamic of split loyalties for Blaney's sister and potential bragging rights on the line in the Byron and Blaney households.

"She has a great chance of celebrating," Byron said before discussing the off-track relationship he's developed with Ryan. "We race hard. We talk about it. We discuss things in the past. I feel like we've gotten to a really good spot where we race each other hard and fair.

"We're both going to be going for it on Sunday trying to win. Nothing changes there. But, yeah, when we get off the track, we spend time together and hang out. I'd say it's like two different dynamics. At the same time that off-the-track relationship allows us to race with good respect, good trust and race hard."

For his part, Blaney insisted the outcome of Sunday's Championship Race won't have an impact on who does and doesn't come to Thanksgiving dinner during the offseason. However, he did acknowledge that his sister has far greater odds of being able to celebrate a championship than anyone else in the garage area.

"I told Erin, 'You've got the best percentage of anybody, of someone you care about winning this thing. You got a better chance than us, all four of us sitting up here,'" a laughing Blaney said. "It is a funny dynamic. At the end of the day he and I still understand we're both competitors, but we're going to race each other with respect, too."

Larson vs. Bell's biggest stage ever

Over and over again in their racing careers, Kyle Larson and Christopher Bell have had to race each other for race wins in massive moments. The two have battled over and over again in sprint cars, most notably at the famed Chili Bowl National, and their racing rivalry proceeded to carry over into the NASCAR Xfinity Series before fully maturing in the Cup Series.

Just a few weeks ago in Las Vegas, it was Larson vs. Bell again as the two fought for the win in the closing laps, with Larson beating Bell to the flag by a carlength to become the first driver to clinch a Championship 4 spot. Bell earned his a week later at Homestead, leaving the two to yet again do battle and size each other up before the green flag on Sunday.

"Christopher is just a guy you can never count out," Larson said. "He's proven that in the NASCAR stuff -- Homestead, for instance, like not even being anywhere in the picture, then here he comes out of nowhere and wins the race. He's done a really good job, him and his team have, of being able to capitalize on things, executing the ends of the races really well and closing them out.

"He does a lot more than that really good, as well. It's cool to see another dirt guy run as good as him, have another dirt guy in the Final 4."

"Kyle, his strength is his raw talent, his ability to drive the car. His 100% — or the better way to say it is his 90% is everyone else's 100%," Bell said. "He's able to run the car at the ragged edge a lot easier than what the other people can. That's his strength."

While this is the first time the two are in the Championship 4 together, both Larson and Bell will be making their second respective Championship 4 appearances. Larson prevailed in the 2021 Championship Race to win his first Cup title, while Bell finished 10th at Phoenix in last year's Championship Race to earn a third-place finish in the 2022 championship standings.

New tire for Phoenix

One of the most major variables in determining the 2023 Cup Series champion will be exactly who takes to a new tire combination for this weekend in Phoenix. In the interest of creating more lap time falloff, Goodyear has brought a different tire to Phoenix than what was run in the spring race, instead using the same tire setup that was run at New Hampshire Motor Speedway in July. The tire in question increases grip while also creating tire wear, theoretically increasing the importance of fresh tires over track position.

While Phoenix and New Hampshire are both mile-long racetracks, that's where the similarities between the two end. That creates a strong emphasis on Friday evening's extended practice session, where the field will get 50 minutes to work through three sets of tires and draw their conclusions from there.

"New Hampshire is nothing like this place. I just remember not feeling like I had very much grip at all in New Hampshire. All of us kind of struggled," Larson said. "... We're probably all excited to get on track on Friday and get an idea how our weekend will be."

Nuts and bolts

• William Byron has quickly put himself in position to become The People's Champion. Instead of taking a private jet from Charlotte, N.C. to Phoenix, Byron took not only a commercial flight, but also the middle seat in Row 29 of the plane. Byron said he didn't wanted to jinx his Championship 4 chances, so he had to make late arrangements after securing a spot at Martinsville.
• Ryan Blaney, a hardcore Star Wars fan, admitted he was "stung" that best friend Bubba Wallace got to film a commercial with Mark Hamill as Wallace unveiled an X-Wing inspired paint scheme, firesuit and helmet as part of a promotion between Star Wars and Columbia Sportswear. Despite his jealousy, Blaney said he was happy that Wallace got to meet Luke Skywalker himself -- "Even though he never has seen Star Wars in his life".
• Despite the fact that Kyle Larson and William Byron both race for Hendrick Motorsports and are competing against each other for the championship, both downplayed that the working relationship between the No. 5 and No. 24 teams are any different for Phoenix compared to other weeks. Larson described the relationship between the two teams as "pretty typical," while Byron mentioned that crew chiefs Cliff Daniels and Rudy Fugle are continuing to share setup information.
• When asked if there is anything he enjoys doing while in the Phoenix area, Christopher Bell -- like many in the NASCAR industry when they head west -- pointed to eating at In-N-Out Burger as a highlight. Bell said he has yet to visit In-N-Out this weekend, saying that he will make his trip on either Sunday or Monday depending on the outcome of the Championship Race.