JOLIET, Ill. – Martin Truex Jr. stretched his arms to his side and waited for a shower of green slime, the colored goop traditionally poured over the heads of game-show contestants and A-list celebrities.

Add NASCAR race winner to the list.

"It's a lot funner to watch people get slimed than it is to get slimed," a smiling and sticky Truex said. "But it's definitely worth it to get that after the race."

Truex backed up his regular-season dominance with a victory Sunday in NASCAR's playoff opener, the Tale of the Turtles 400 at Chicagoland Speedway, that solidified him as the driver to beat over the final nine races.

He raced to his fifth victory of the season and earned an automatic berth in the second round of the playoffs, piling on more points in his bid to compete for the title in the finale at Homestead.

A driver with three Cup wins in his first 10 seasons, Truex has nine over the past two years for Furniture Row Racing.

"I think we all realize it's just a unique time in history, in all our lives, that this has come together," team owner Barney Visser said.

Truex was in cruise control over the final 55 laps and built a nearly seven-second lead over Chase Elliott in winning at Chicagoland for the second straight season. Truex's car flunked inspection following the win last season, and the No. 78 Toyota ran into more issues Sunday — the car needed four tries through pre-race inspection before it was cleared, and Truex later overcame an early pit-road penalty.

"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 playoff drivers Kevin Harvick, Denny Hamlin and Kyle Larson.