JOLIET, Ill. — Asked what drivers worry him as he seeks a second-straight Sprint Cup title, Kyle Busch identified Kyle Larson and Martin Truex Jr.

Both compete for smaller teams that get engines and other technical support from the large, multi-car organizations. And their success heading into the start of NASCAR’s 10-race playoff Sunday at Chicagoland Speedway is starting to annoy the big boys.

“It hurts to be outrun by somebody in your equipment,” six-time champion Jimmie Johnson said.

Of the 16 drivers to qualify for the season-ending Chase, half are from teams outside the behemoth organizations of Hendrick Motorsports, Joe Gibbs Racing and Team Penske.

“It’s a slippery slope,” Johnson said. “I mean, I think that Gibbs and Hendrick and these bigger teams will really have to think hard about alliances that they put together.”

Hendrick, Johnson’s team, makes engines for Chip Ganassi Racing, which employs Larson. Gibbs, Busch’s boss, has an alliance with Furniture Row Racing and Truex.

Stewart-Haas Racing, which has three drivers in the Chase, gets its engines from Hendrick and it has fueled a rivalry between Johnson and Kevin Harvick. But that agreement ends after the season when SHR shifts from Chevrolet to Ford, leaving for some awkward moments as the teams share information this season.

The deals are in place to cut down on costs for the smaller teams and also provide overhead relief for the big teams while ensuring a healthy number of entrants, which had been declining.

“I’ll use Stewart-Haas as an example for us. They get our best stuff, and they’re not a small organization. They have a huge engineering staff,” Johnson said. “So they take our best equipment, that’s part of the deal, fully refined, what we’re racing, then their engineering staff gets to work on it and make it better. 

“Same thing is going on at Gibbs. They’re providing all that equipment to the 78 (Truex) car, and they’re smart people. That’s pretty good, but I’m going to tweak this and that, and they make it better yet.”

It’s brought a different dynamic to the third year of the current Chase format, which calls for three rounds of elimination before the Nov. 20 finale at Homestead. Johnson, the No. 8 seed, is the highest-ranked Hendrick driver in the field.

Johnson has had uncharacteristic mistakes this season as he aims for a seventh title, which would tie the record for NASCAR’s top circuit held by Richard Petty and Dale Earnhardt.

“I don’t like where we’re at,” Johnson said. “We’re working hard. There’s a lot of optimism and a lot of great things happening. We just need to deliver consistently and execute at the track.” 

Busch has led the most laps this season and will start Sunday’s race from the pole after qualifying Friday was rained out. But Busch is far from comfortable with Truex having so much success in his own Toyota.

“Even though we’re top seed, we may not be the favorite right now,” Busch said. “Actually, I’d probably look at the 78 car for having the most raw speed here as of late. That’s the guy we’re probably all chasing at the moment.”

Busch also had praise for Larson, who won at Michigan and joins Jamie McMurray to give Ganassi two drivers in the Chase for the first time. Busch called Larson a good fantasy league pick.

“He’s cheap but, man, he can definitely punch out the results,” Busch said. “And they’ve shown that the last couple of weeks of having good cars and good speed and being right there in the running for the final finish.”

Larson, in his third season in the Sprint Cup, is confident entering his first Chase because of his success on 1.5-mile tracks like Chicagoland.

“I’ve ran good at most all of them in the past, specially 2014 we had a good run in the last 10 races,” Larson said. “Even last year there were a couple where we did well at. I could have won Homestead last year had that caution not come out at the end.”

For the competitive Busch, the evening of the field has provided more motivation to beat the likes of Truex, who had a dominating win at Charlotte.

“Given that we’re within the same organization, same team, and have all the same stuff, it’s on us as the 18 team,” Busch said, “It’s on us to be able to go out there and race and get the same or better results than they can.”