FONTANA, Calif. --- Jimmie Johnson showed little mercy on his competition in the Chase for the Championship -- or anyone else -- during Sunday's Pepsi 500 at Auto Club Speedway.

On an afternoon in which half of the teams in the playoff field had problems, Johnson was never better. He easily moved to the front whenever he wanted, leading a total of 10 times for 126 laps. None, however, was more important than the final six after a 23-minute red-flag period to clean up an eight-car crash.

In the process, Johnson passed Mark Martin for the Chase lead in an attempt to win his fourth Sprint Cup Series title in a row. Johnson leads Martin by 18 points.

"That was monumental," said crew chief Chad Knaus.

When it comes to stock car's postseason, none has excelled like Johnson. The victory was his 16th in 54 playoff races.

"What an awesome car; what an awesome day," Johnson said. "That caution at the end of the race really had me nervous. I didn't know what to do on the re-starts. I'm glad I got a good start and got going."

Johnson dominated during long stretches in the first 400 miles. He also dominated when the pace was slowed by a rash of late cautions.

He started beside Hendrick Motorsports teammate Jeff Gordon with three laps to go and he had no trouble pulling away to a 50-yard win before one of the smallest crowds of the season.

Gordon settled for second, while Juan Pablo Montoya was third. Montoya is the only driver to have four top-five finishes in four Chase races.

"You ain't going to make points on anyone," Montoya said. "It's amazing that I have four top-five finishes and I'm losing ground. When it was cooler (early in the race) I had a better car. When it got warmer, he had the better car."

Montoya started the playoffs 40 points behind Martin. Now he's in third place, 58 points behind.

Martin was fourth, followed by Tony Stewart, Carl Edwards, David Ragan and Kurt Busch. The only driver not in the Chase among the top eight was Ragan.

The other drivers in the playoffs had problems. Crashes hurt the chances for Denny Hamlin, Greg Biffle, Brian Vickers and Kasey Kahne. Stewart fell off the lead lap early with a speeding penalty on pit road and Busch's car was damaged in a crash involving Kahne and Biffle.

Reach Don Coble at don.coble@morris.com.