JOLIET, Ill. — Brad Keselowski began the season with a bit of goofiness, posting on Twitter during a red-flag stoppage at the Daytona 500.
He's ending the year with a far more serious pursuit: his first Sprint Cup championship.
Keselowski scored the first Chase victory of his career, outlasting Jimmie Johnson in the GEICO 400 on Sunday at Chicagoland Speedway. In winning the Chase opener, Keselowski also took over the lead in the points standings for the first time.
"There's no better place to start than in the lead, right?" Keselowski said. "It feels like Round 1 of a heavyweight title bout. It's a 10-round bout, and Week 1's done. We might have won the round but didn't by any means knock 'em out."
Keselowski and his No. 2 Dodge got ahead of Johnson after a crucial pit cycle with about 35 laps remaining and led the final 26 laps in the 400-mile race. Johnson finished 3.171 seconds behind, and he said he thought Keselowski crossed a restraining line too early when exiting after that pit stop near the end.
The incident was reviewed, and there was no infraction called. Johnson never made much of a run at Keselowski during the final laps.
"He did cut up early. It did impede my progress," Johnson said. "But it didn't affect the outcome, I don't believe. The way he made quick work in traffic and stretched it out on me, I'm not sure I would have held him off."
All 12 of the Chase drivers finished in the top 18, with the exception of Jeff Gordon, who went into the wall with about 80 laps left. Gordon barely qualified for the Chase, and his title hopes are already in serious jeopardy after his 35th-place showing.
It was Keselowski's fourth victory of the season. The Michigan driver leads Johnson by three points and gave Penske Racing a reason to feel good after Will Power's failed bid Saturday for the IndyCar championship.
Denny Hamlin, the top Chase seed coming in, fell to 16th in the race while low on fuel at the end.
There were only four cautions for 23 laps, the last coming when Gordon said his throttle became stuck, causing a crash.
"Disappointing," said Gordon, who started the race in the 19th position. "We had to fight hard to come from 19th up there in the top five, and the car was feeling good."
Keselowski has finished in the top 10 in 10 of the past 11 races. He began the year with a late accident at Daytona. Earlier in that race, he caused a bit of a stir when he posted on Twitter during the red flag. Afterward, NASCAR said it was okay for him to keep his cellphone in his car and all drivers were encouraged to use social media.
Naturally, Keselowski posted on Twitter and included a photo: "WE did it! Victory lane with roger penske."
But lately, Keselowski's driving has been drawing the attention.
"I just think Brad does a nice job," Chase driver Kasey Kahne said. "As far as the championship, I don't think anyone knows that until you actually win it."
Johnson had won five titles in a row until last year, and it looks as if his car is a threat again. He won the pole this weekend and finished in the top 10 for the ninth time in 11 Cup races at Chicagoland, although he has never won. He led 172 of the 267 laps Sunday.
"We all know how good his team is," Keselowski said. "To be racing him, whether it was for the lead or for 10th, is an accomplishment."