AVONDALE, Ariz. — In one of the most remarkable comebacks in recent memory, longtime fan favorite Justin Allgaier, at last, claimed the NASCAR Xfinity Series championship trophy Saturday night at Phoenix Raceway — coming from a lap-down mid-race in a back-up car to hoist the shiny hardware.

Stewart-Haas Racing‘s Riley Herbst‘s No. 98 Ford passed Allgaier‘s No. 7 JR Motorsports Chevrolet for the NASCAR Xfinity Series Championship Race win on the last lap of double overtime for his second win of the 2024 season and joined the new series champ Allgaier in twin celebratory burnouts on the front stretch of the mile-track.

“I said all weekend, I don‘t know what the plan is, but HE has a reason for everything and tonight is true of that, this is mind-blowing, it really is,” said Allgaier, his voice already hoarse and strained from screaming in happiness, but the smile unshakable as his young daughters came in for a hug for dad.

“This team never gave up. [Crew chief] Jim Pohlman and his leadership skills are second to none. He told me all weekend that we were going to have a chance and we tried to give it away every way we could.”

WATCH: Allgaier shows his emotions after first Xfinity title

It was an emotional outcome for the 38-year-old Allgaier, who joked that he was just trying to make the race exciting for the fans. He has qualified for the Championship 4 seven times, finishing runner-up twice including last year.

And now he could finally celebrate. Allgaier‘s team owners, NASCAR Hall of Famer Dale Earnhardt Jr. and his sister Kelly Earnhardt Miller joined Allgaier‘s longtime sponsor Rick Brandt on pit road. They were overjoyed to congratulate their driver who overcame a weekend of obstacles to finally claim this historic moment — and it came on a night when the sport observed a moment of silence to honor another great champion, NASCAR Hall of Famer Bobby Allison, who passed away earlier Saturday.

The obstacles Allgaier faced happened well before the race‘s green flag. His primary car was destroyed in a crash four laps into Friday‘s opening practice session after running over oil on the track from another car that ultimately forced four drivers into back-ups for the race. The car swap meant Allgaier started last in the 38th car field Saturday night, but the always upbeat 14-year veteran of the series had moved into the top 10 by lap 26.

Then, after all that work, Allgaier was called for a restart violation on Lap 101 and sent down pit road for a penalty … only to be called for speeding on the way out and penalized with another trip down pit road — both penalties served during green flag racing. After the penalties, Allgaier dropped to 35th on-track and was a lap down on Lap 107 of the scheduled 200-lapper.

He got a huge break in fortune with a caution period with 45 laps remaining — opting to stay out and get back on the lead lap. He stayed in the top 10 and worked his way forward – moving from sixth place to second on the first overtime restart. He started on the front row of the second overtime restart but was passed on the final lap by Herbst for the race win. Allgaier‘s second-place finish was still good enough to land the championship, however.

RELATED: Unofficial results | At-track photos: Phoenix

It marked the third career win for the 25-year-old Las Vegas native Herbst, who crossed the line .247-second ahead of Allgaier and led a dominating 167 of the 213 laps.

“I knew we were going to have a fast race car, these guys have been working on this race car and I knew we were going to be really really fast,” said Herbst, whose SHR team is closing at the conclusion of the season. “It‘s been a really tough week at the shop, really emotional time. I‘m forever grateful to every man and woman at Stewart-Haas Racing they gave me a really fast car today and I can‘t thank everyone enough.”

It was actually fellow championship contender — reigning champ Cole Custer — who mounted the most consistent challenge to Herbst. He ran up front for most of the race, just off the pace of his SHR teammate and ultimately finished eighth in the No. 00 SHR Ford — his effort answered last year‘s title with a runner-up in this year‘s championship standings.

The other two championship contenders, Kaulig Racing‘s AJ Allmendinger and Richard Childress Racing‘s Austin Hill finished ninth and 10th. And as disappointed as the three title contenders were in not claiming the season championship, each conceded the night had a positive ending with their longtime competitor Allgaier finally getting that trophy after 14 years of competition in the series.

“I‘m really happy for Justin, that was a long time coming,” said Custer, who will compete in the NASCAR Cup Series full-time next season. “He‘s definitely a deserving champion and they ran a great race, especially there at the end.”

Hill, making his first Championship 4 appearance, agreed with the sentiment.

“Justin Allgaier has been doing this for a really long time and to see him finally get it done, I‘m really happy for him and happy for his family,” he said. “He‘s a great guy to be around, a great competitor.

“He‘s going to be a great champion for the Xfinity Series. I‘ve enjoyed racing that 7 team all season long. If I couldn‘t have gotten the championship, I‘m glad he was the one that got it done.”