AVONDALE, Ariz. — In her short 11 years, Harper Allgaier only has known disappointment and pain when it came to the NASCAR Xfinity championship race for her daddy Justin.

Two years ago, she cried after he led late in the title race before he finished third while Ty Gibbs won the championship.

Saturday night, Harper cried again. The tears came after she ran to her father and hugged him by his car.

These were happy tears.

Allgaier had just won his first Xfinity Series championship in his seventh appearance in the title race.

“I was just so happy and overwhelmed that it just kind of came,” Harper told NBC Sports.

She had never cried happy tears before.

“Tonight was so cool because I think she saw a side of me that she’s never seen,” Allgaier told NBC Sports. “I feel like when she is older, these are the moments that I think are going to really mean something to her, and it was cool to be able to celebrate with her.”

Allgaier’s journey to Saturday night’s championship has been one of family with wife Ashley and daughters Harper and Willow.

“Family is what started this sport for me,” Allgaier said of his parents Mike and Dorothy. “It’s what has carried the sport for me. It’s what I will always go back to. They’re the most important piece.

“Having them all here tonight and to celebrate and to be part of it … there are no words.”

Allgaier won the championship wearing a helmet designed by Harper. She’s helped design his helmets since she was 4 years old.

That first one featured her handprint in pink. She had a message on the back of his helmet that read: “Get up on the wheel, Daddy. Love, Harper.”

This year’s helmet featured a horseshoe, which had special meaning. Justin’s grandfather always carried a horseshoe in his pocket.

“When my grandfather passed away, we actually did kind of a little memorial sticker for my grandfather and it was literally that horseshoe, and I ran that on all my race cars,” Justin said ahead of the helmet’s debut in the playoffs. “… (Harper) knows my relationship with my grandfather, how much he meant to me and my racing career and how much I miss him.”

Harper continued the tradition of putting a message on her dad’s helmet. She added her younger sister, 3-year-old Willow, to it this year.

The message:

It’s your lucky year. Go have some fun and win some races! Love Harper and Willow

But it seemed as if this year’s race would also end in disappointment for Allgaier and his daughter.

Allgaier crashed in practice Friday after only three laps when another competitor’s blown engine put fluid on the track and sent several cars sliding into the wall. Allgaier had to go to a backup car, forcing him to start at the rear of the 38-car field Saturday.

Allgaier’s title chances seemed over after he was penalized for a restart violation at Lap 100 and then penalized for speeding on pit road as he served the first penalty. He dropped to 35th.

Dale Earnhardt Jr., who owns the JR Motorsports team with sister Kelley Earnhardt Miller and Rick Hendrick that Allgaier drives for, can relate to what Harper has gone through in the past.

As Earnhardt held an 8-foot flagpole carrying the champion’s banner, the 50-year was transported back in time to 40 years ago and the memory of his dad racing at Bristol.

“Dad was leading the race,” Earnhardt said. “Something happened where he got turned around on the front straightaway and he spun. I was sitting on top of a van, dead center of the racetrack in the infield. I could see him spin and I’m like, ‘It’s OK,’ but his tires were flat and he couldn’t get going and they lapped him.

“I was old enough to realize what was going on and my heart was so broken. … It scarred me.”

There would be no such pain for Harper on this night.

The race changed when Anthony Alfredo wrecked to bring out the caution 45 laps from the scheduled distance. It came in the middle of a green-flag pit cycle, allowing Allgaier to get back on the lead lap.

Allgaier climbed through the field and finished second to Riley Herbst, who was not racing for a championship, in overtime. Allgaier was the highest finishing title contender.

Allgaier was a champion.

And a daughter couldn’t get to her father fast enough.