FONTANA, Calif. -- Jimmie Johnson knew it was time to take a more commanding role.
With crew chief Chad Knaus removed by NASCAR, Johnson and the rest of the No. 48 Chevrolet team responded with a unified effort in winning the Daytona 500 last week.
Lead engineer Darien Grubb filled in for Knaus on race day as Johnson earned the 19th win of his Nextel Cup career.
Johnson, a two-time series runner-up who has never finished lower than fifth in his four full Cup seasons, wants to take the next step and win a championship.
When NASCAR tacked on another three races to Knaus's suspension for an unapproved change to the rear window of Johnson's car during Daytona qualifying, the driver decided to do more than simply support Grubb and the rest of the crew.
''Chad is such a strong leader," Johnson said. ''His personality really does it on its own, and that's an area I need to focus on. The guys want me to be a little bit more in that role. And, now, with our latest situation, I'm the senior guy."
Johnson is certainly leading on the track -- he has the victory in Daytona and a solid third-place qualifying run for today's Auto Club 500 at California Speedway.
''But I'm just trying to be around for the guys, too, and keep the spirits up," Johnson said. ''When anybody has time to sit and think, that's when you get nervous. But, if I stick around and keep the guys pumped up and smiling and keep positive energy rolling, everything's in good shape."
Johnson will be starting today's race behind Kurt Busch and Greg Biffle.
Busch, the pole-winner, is trying to win for the first time with his new team, Penske Racing South. Despite winning the 2004 Cup title for Roush Racing, Busch was often under NASCAR scrutiny for aggressive driving. He left Roush under a cloud, banned for the final two races of 2005 after a traffic stop in Phoenix during which he became belligerent with police.
Now, moving into the No. 2 Dodge that the retired Rusty Wallace drove, Busch is projecting a new attitude and looking for a fresh start. He drove a strong race at Daytona before a crash relegated him to 38th place. He won the pole Friday, the fourth of his career but first since 2004.
''For a team that's new, we're just feeling each other out and getting comfortable," said Busch.