SPARTA, Ky. (AP) -- Imagine what he might have done with his fastest car.
"It wasn't the newest car we got, but it runs," Keselowski said.
The 28-year-old from Rochester Hills, Mich., picked up his seventh win in his five years on the circuit. He won earlier this year at Bristol and Talladega.
Kasey Kahne rode a late surge to second place, 4.399 seconds back of the winner.
So well was Keselowski running that Kahne, despite his fast finish, knew he needed help to catch him.
"I just hoped he'd run out of gas," Kahne said, grinning. "No way I was catching him. We had stopped (for a fill-up) and I was hoping he'd shut down."
Keselowski had just enough fuel to finish.
While registering his 16th career top-five finish in the 267-lap race, Keselowski, who led for 68 total laps, ended a lull over the past four starts where he had failed to crack the top 10.
He was driving his backup car after slamming the right side of his top car into the wall in the wake of a collision with Juan Pablo Montoya during practice earlier on Friday. That mishap took place on his very first lap on the track.
Denny Hamlin was third, Dale Earnhardt Jr. fourth and Jeff Gordon fifth. Hamlin announced a new agreement with Joe Gibbs Racing on his Twitter account just before the start.
"It's a great day," he said, although he was disappointed that his car hadn't run better. "When you know you're locked in where you're going to race for really long time, it's a good feeling. Those guys (at JGR) have given me a championship-caliber racing team."
A year after severe traffic congestion resulted in thousands of angry fans, there were few glitches after the track and government officials widened ramps and roads and added 20,000 parking spaces.
Defending champion Kyle Busch was dominating for most of the first half of the race before he bumped into the wall and had to fight suspension problems -- a broken shock absorber -- that dropped him off the pace.
With an uncharacteristic white paint job on his Chevrolet, pole-sitter Jimmie Johnson led at the 200-lap mark but fell back all the way to 11th due to a flat tire. He finished sixth.
Matt Kenseth, in action for the first time since announcing that he was leaving Roush Fenway Racing after the season, surged late to place seventh.
Rounding out the top 10 were Martin Truex Jr., A.J. Allmendinger and defending champion Kyle Busch, who dominated most of the first half of the race before hitting the wall and breaking a shock absorber that dropped him off the pace.
Tony Stewart fell to the back of field early after fuel-injection problems.