JOLIET, Ill. — Martin Truex Jr. backed up his regular-season dominance with a victory Sunday in NASCAR’s playoff opener at Chicagoland Speedway.

Truex solidified himself as the driver to beat over the final nine races as he chases his first Cup championship. Truex raced to his fifth victory of the season and an automatic berth in the second round of the playoffs, earning even more points in his bid to compete for the title in the finale at Homestead.

Truex had a nearly 7-second lead over Chase Elliott in the final laps and won at Chicagoland for the second straight season.

“I don’t really care a whole lot about statements. I’m just having fun,” Truex said. “It’s important to come here and not let the pressure get to you, and I think we did a good job with that.”

Elliott was second, followed by Kevin Harvick, Denny Hamlin and Kyle Larson.

Truex’s No. 78 Toyota needed four tries through pre-race inspection before the car was cleared and later overcame an early pit-road penalty. By the end, there was no doubt the path to the NASCAR championship goes through Truex.

Truex won this race last season – also holding off Elliott for the second straight time – and again seemed right at home on the 1.5-mile track. Truex had wins this season on 1.5-mile tracks at Las Vegas Motor Speedway, Kansas Speedway and Kentucky Speedway.

Truex had a win snatched from him last week at Richmond because of a late caution and he ended up crashing. He and his team looked downright miserable accepting the regular season title trophy.

Truex’s longtime girlfriend, Sherry Pollex, was by his side in victory lane and stepped away from the slime. Pollex is battling a recurrence of ovarian cancer.

“I’m a lot better driver these days because of her and what she’s been through,” he said. “We’ve learned a lot about life together. We continue to face every challenge head on and not scared.”

He might have other drivers green with envy – but it was Truex who was slimed in the colored goop made famous by Nickelodeon as part of the race sponsorship. The Furniture Row Racing crew was bathed in slime and champagne during a raucous victory lane celebration.

He entered the playoffs at the No. 1 seed with four wins, 18 stage wins and he totaled a whopping 53 bonus points that he can keep through the first three playoff rounds.

Truex leads the standings by 27 points over Larson.

Chicagoland was site of the playoff opener for the final time. NASCAR will kick off the 10-race postseason next year at Las Vegas.

Two races remain before the playoff field is cut to 12. The NASCAR postseason shifts to New Hampshire Motor Speedway, the final fall race for the track. Hamlin won the summer race at New Hampshire and Harvick won the September race last season.