JOLIET, Ill. — Martin Truex Jr. went from a completely unraveled tire that left him a lap down to the NASCAR Chase for the Sprint Cup championship lead for the first time in his career.

He can thank a late caution in what has been an emotional year for the small-team driver.

Truex shot to the front after a late restart and pulled away to give Furniture Row Racing a NASCAR Sprint Cup playoff-opening victory Sunday in the Teenage Mutant Ninja Turtles 400 at Chicagoland Speedway.

“I've had a lot of practice at it,” Truex said of the on-track obstacles. “I think my approach really changed two years ago when Sherry [Pollex, his girlfriend] got diagnosed with cancer. My approach to all those things changed and made me a better driver.”

NASCAR announced after the race that Truex's No. 78 Toyota failed the laser inspection, but the infraction was not serious enough to negate the victory for Chase qualification purposes. Truex is expected to receive a point penalty this week.

Rookie Chase Elliott appeared on his way to an easy win until Michael McDowell blew a tire and spun out to bring a caution with five laps left.

Elliott and Truex came in to pit for tires, while non-Chase drivers Ryan Blaney and Kasey Kahne and Chase contender Carl Edwards stayed on the track.

Truex restarted fourth and Elliott fifth, and Truex quickly got to the front and held off Joey Logano on the final lap for his third victory of the season. Truex is guaranteed to move on when the Chase field is cut from 16 to 12 in two weeks.

Truex, whose team gets technical support from Joe Gibbs Racing, made the last four in the 2015 Chase. His 2016 season started with a near-miss at the Daytona 500 and a Coca-Cola 600 win, while Pollex has battled ovarian cancer. She's now in remission.

“You have to understand, this isn't the end of the world,” Truex said of racing setbacks. “We can overcome it. That's what we did today.”

Elliott, a rookie, finished third, followed by Blaney and Chase driver Brad Keselowski, who sits second in points.

“It's not yours until it's over,” the 20-year-old Elliott said. “That's part of life, man. You're not dumb. We've all watched this stuff long enough to know these races don't go green that long.”

Truex led early in the race, only to have his tire come completely unraveled. It led to an unscheduled stop that left him a lap down in the 400-mile race.