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A.J. Allmendinger conserved enough fuel and held off Justin Allgaier after three restarts in the closing laps to win Saturday's Nationwide Series race at Road America.

Allmendinger's first win in a NASCAR national touring series race came nearly one year after he was placed on suspension for violating the sanctioning body's substance abuse policy. He was released from his Sprint Cup ride at Penske Racing following his failed drug test. NASCAR reinstated Allmendinger later in the season when he successfully completed its "Road to Recovery" program.

Earlier this year, Allmendinger rejoined Penske to compete in several IndyCar Series races, including the May 26 Indianapolis 500, in which he finished seventh. Team owner Roger Penske then hired Allmendinger to compete in two Nationwide road course events, driving the No. 22 Ford.

"It's understated what Roger has done for me," Allmendinger said. "All these guys at Penske Racing gave me another chance not only to drive Indy cars but get in this Nationwide car."

Allmendinger started on the pole and led a race-high 29 laps. The scheduled 50-lap event at this four-mile road course featured five additional laps due to two green-white-checkered attempts.

Allmendinger was running in fourth for a restart on lap 43 but moved up on the bumper of leader Billy Johnson and pushed Johnson off the course, allowing Allgaier to slip by and take the lead. One lap later, Allmendinger passed Allgaier and took the lead for good.

The first two-lap overtime finish was set up when John Young ran out of fuel and came to a stop on the track. After the restart, Michael Annett spun around in turn 7 when he was hit from behind by Owen Kelly. Annett could not get his car to move back onto the course, forcing NASCAR to display the caution flag and therefore setting up another attempt at a green-white-checkered finish.

Allmendinger pulled away from Allgaier following the last restart and then beat Allgaier to the finish line by 1.37 seconds for his first Nationwide win in his ninth start. He had not competed in the series in five years.

"I was trying so hard out there and at times probably trying too hard," Allmendinger said. "Those late-race restarts were starting to frustrate me, and (crew chief) Jeremy (Bullins) was pretty good about calming me down."

Allmendinger won a Champ Car race at Road America in 2006.

While Allmendinger drove into victory lane, tempers flared between Max Papis and Johnson on pit road after both of them had a run-in late in the race. Papis walked over to Johnson and slapped him on the helmet to express his displeasure.

"I shouldn't have slapped him, and I apologize," Papis said. "My temper got me. I'm disappointed because he ran me off the track. We were having a great race."

Johnson finished 15th and Papis 17th. Both drivers were running in the top-10 when their incident occurred.

"That was my fault," Johnson said. "Everybody was checking up really early, and I got into the back of (Papis). This road-course racing is pretty intense."

Parker Kligerman finished third, while Kelly took the fourth spot. Sam Hornish Jr. was fifth.

Brian Vickers, rookie Kyle Larson, Cole Whitt, Elliott Sadler and Austin Dillon completed the top-10.

Points leader Regan Smith finished 32nd after he spun around into the gravel on the final lap. Smith now holds a 28-point advantage over Allgaier, who moved up to second in the standings with his runner-up finish.

"It's frustrating to be second and not be in victory lane," Allgaier said. "Even though we finished second, it was a great day for us. We battled through some adversity earlier and were able to come back and have a good run, so I'm really proud of that."

Hornish is 30 points behind Smith.