Employing a unique pit strategy that saw him pit from the lead with less than 50 of 300 laps remaining, Allgaier powered through the field from 13th on new tires and moved back out front with 12 to go.
From there, he was able to put some distance between himself and Hemric and cleared him by 1.685 seconds to earn his second career win at Bristol (Tenn.) Motor Speedway.
The victory locks Allgaier into the semifinal round of the playoffs regardless of his finishes in the next two races. The win is the third for Allgaier this season and 22nd of his career.
As a bonus, Allgaier announced during his post-race interview that he had signed a contract extension earlier this week to return to JR Motorsport’s No. 7 Chevrolet next season.
“I just cannot say enough about this team. This team has done such an amazing job at this race track since I started at JRM. We’ve led a lot of laps and the monkey was definitely on my back,” Allgaier said.
“The pit strategy there – coming down pit road all by myself, that was nerve-racking. I’m speechless, man. This place is special to me.”
John Hunter Nemechek ended up third, Cole Custer was fourth and Chandler Smith rounded out the top five.
Completing the top-10 were Ryan Sieg, Trevor Bayne, Riley Herbst, Sammy Smith and Kaz Grala.
With two races remaining in the second round of the playoffs, the four drivers lowest in points without a win and in danger of further title elimination are Sam Mayer, Josh Berry, Parker Kligerman and Jeb Burton.
NASCAR Hall of Famer Dale Earnhardt Jr., making the first of two Xfinity starts this season, had an eventful night.
He ran up front, led 47 laps and remained in contention for the win until late in the final stage when he was forced to pit when smoke began to fill the cockpit of his No. 88 Chevrolet. He finished 30th.
Custer, who started on the pole, completely dominated, and led all 85 laps on his way to a 3.204-second Stage 1 win over Allgaier. Brandon Jones was third, Nemechek was fourth and Smith rounded out the top five.
Allgaier claimed the Stage 2 win under caution when his three JRM teammates – Berry, Mayer and Jones – got collected in a wreck with two laps remaining.
Berry got into Mayer to trigger the wreck and Jones and Ryan Sieg both got into the spinning car of Berry.
During the break between Stages 2 and 3, most of the lead-lap cars pit but Earnhardt remained on the track and inherited the lead. He led Bayne and Chandler Smith on the restart with 121 laps to go.
With 100 laps left in the race, Earnhardt maintained an almost 2-second lead over Custer, who was followed by Bayne and Allgaier.
On lap 217, Sheldon Creed turned his Richard Childress Racing teammate Austin Hill on the frontstretch, which sent Hill – the regular season champion – into the wall. Hill was knocked out of the race.
A handful of lead-lap cars pit but Allgaier stayed on the track and retook the lead. The race resumed with 76 laps remaining.
A spin by Josh Bilicki brought out the sixth caution of the race but most of the lead-lap cars remained on the track. Allgaier did elect to pit for new tires which turned the lead over to Hemric on the restart with 44 to go. Allgaier restarted in 13th.
With less than 30 laps remaining, Earnhardt’s No. 88 Chevrolet suddenly fell off the pace and he drove it down pit road. “I’m on fire, boys,” Earnhardt said over his team radio as he quickly got out of his car.
Allgaier, on new tires, caught Hemric for the lead with 20 laps remaining and began working on him to attempt a pass. He finally was able to power around Hemric to reclaim the top spot with 12 laps to go.