Denny Hamlin passed Kurt Busch with five laps to go to win Sunday afternoon's MyAFibRisk400.com, the opening race of the Chase for the NASCAR Sprint Cup Series.
It was the second victory of the season for Hamlin and the 12th of the year for Joe Gibbs Racing. Carl Edwards finished second to make it a JGR sweep of the top two positions. Kurt Busch, Ryan Newman and Matt Kenseth completed the top five.
By virtue of his victory at Chicagoland Speedway, Hamlin is guaranteed to advance to the second round of the Chase, no matter where he finishes in the final two races of the Challenger Round of the Chase.
More from FoxSports
Hamlin hung on to win despite being on old tires. Among the leaders, only he, Jeff Gordon and Kurt Busch decided to stay out on the track before the final restart.
"What an amazing day ... just amazing," Hamlin marveled over the team radio shortly after taking the checkered flag.
Edwards, who had four fresh tires, thought he was going to be able to run Hamlin down.
"My guys just do a great job on pit road, they really do," Edwards said afterward after rallying from a pit-road speeding penalty of his own. "(Crew chief) Darian (Grubb) never loses his cool ever. He played the game perfectly with pit strategy.
"Then at the end, truly, once we got into Turn 1 on the final restart, I was like, 'I got this thing.' I got better tires than all these guys. ... Then I thought, 'Denny is mine, he's a sitting duck.' He drove the wheels off of that thing. He really hung on with those tires that he had."
Indeed, he did. He said he is pleased to not have to worry about where he finishes in the next two races, knowing his victory secured advancement into the next round of the Chase.
"Go have some fun the next two weeks, that's for sure. Takes some pressure off of us," Hamlin said about his strategy for the next two weeks.
It was a bit of a surprise win considering Hamlin -- driving with a torn right anterior cruciate ligament -- had a horrible opening day of practice that cost him when qualifying was rained out Friday. The field was set by practice speed and Hamlin was 29th at the start.
He then spun trying to pick his way through traffic on the second lap, dropped a lap down and was last in the field.
But he and his JGR team didn't panic, then used the gutsy call not to pit during the final caution to give Hamlin a shot at the victory.
He jumped from third to first on the restart with five laps remaining, and gave JGR its ninth win in the last 12 races. JGR has won three consecutive Sprint Cup races, and celebrated an XFiINITY Series victory on Saturday with Kyle Busch.
Sixteen drivers started Sunday's race in championship contention; the bottom four in points will be eliminated when the Challenger Round concludes two weeks from today at Dover International Speedway.
The big loser on the day was defending Sprint Cup Series champion Kevin Harvick, who cut a tire after contact from Jimmie Johnson on a restart on Lap 135. Four laps later, Harvick's left-rear tire failed and he went into the wall. Harvick ended up all the way back in 42nd-place and will have a deep hole to dig out of if he wants to repeat as champion.
Afterward, Harvick punched Johnson in the chest after Johnson tried to approach him in the Sprint Cup garage.
The Associated Press contributed to this report.