HOMESTEAD, Fla. — Here's a tweet for Brad Keselowski: NASCAR champion.

Roger Penske must like the sound of that, too.

The kid who stole the show at the season-opening Daytona 500 ended the year under the biggest spotlight of them all Sunday, beating five-time champion Jimmie Johnson to deliver the first Sprint Cup championship to Penske Racing.

His first act as champion? Sending a tweet, of course, from inside his car: "We did it!" with a picture of the celebration waiting for him.

"Always, throughout my whole life I've been told I'm not big enough, not fast enough, not strong enough and I don't have what it takes," Keselowski said from the championship stage. "I've used that as a chip on my shoulder to carry me through my whole career. It took until this year for me to realize that that was right, man, they were right.

"I'm not big enough, fast enough, strong enough. No person is. Only a team can do that."

So, with the Penske organization behind him, he delivered a trophy that had eluded "The Captain" since his 1972 NASCAR debut. Although his motorsports organization is considered the gold standard of open-wheel racing — 15 Indianapolis 500 wins — and his empire has made Penske one of the most successful businessmen in America, his NASCAR team has always been just average.

Then came Keselowski, the blue collar, Twitter-loving, Michigan native who visited Penske in 2008 convinced the NASCAR team could win, too.

Three years later, they hoisted the Sprint Cup trophy together at Homestead-Miami Speedway following Keselowski's 15th-place finish Sunday night.

"It's all about the people in our organization and obviously Brad coming on our board three years ago, and we set a plan and we stuck to it," the 75-year-old Penske said. "To win this championship is amazing."

Keselowski needed 125 starts to win his first championship, the fewest starts since four-time champion Jeff Gordon won his first title in 93 starts in 1995. Keselowski also won a second-tier Nationwide title in 2010, his first season with Penske and the owner's first official NASCAR championship.

Gordon, who avoided suspension this week but was fined $100,000 by NASCAR for intentionally wrecking Clint Bowyer last week at Phoenix, overcame the controversy to win the race in a 20th anniversary celebration for sponsor Dupont and Hendrick Motorsports.

It was Gordon's first victory at Homestead, which leaves Kentucky as the only active NASCAR track where he's yet to win.

Who did Gordon beat? Bowyer, of course.

And Bowyer's second-place finish moved him to a career-best second in the final standings. Third-place went to Ryan Newman, who got his break in NASCAR with Penske and spent seven seasons driving for the owner.

"He deserves this probably as much as anybody else, if not more because of what he's done for motor racing in general, NASCAR, his dedication to all forms of race cars is probably more than anybody else in the history of auto racing," Newman said. "I know this is probably one of the sweetest moments in his racing career."

Keselowski started the race up 20 points on Johnson, who blew a tire and crashed last week at Phoenix to give Keselowski a nice cushion and needing only to finish 15th or higher in the finale to wrap up his first championship. But the Penske team took nothing for granted — not after Will Power crashed in the IndyCar finale to blow a 17-point lead and lose the championship.

And this one got tight, too, especially when Keselowski ran out of gas on pit road during green flag pit stops. It put him a lap down with Johnson leading, and Keselowski and crew chief Paul Wolfe frantically tried to figure out how dire the situation had become.

Wolfe crunched the numbers, figuring the No. 2 Dodge would cycle out in the mid-20s, a lap down from the leaders.

"I know the scenario, and it's not good," Keselowski said.

But minutes later, Johnson went to pit road for his own stop and pulled away with a missing lug nut. NASCAR flagged the Hendrick Motorsports team and Johnson was forced back to pit road for another stop.

The Penske team was unsure if Keselowski wanted to know what was going on with Johnson.

"I've got a big picture story if you want to hear it," a team member radioed, then informed Keselowski that Johnson had to pit again.

"Ten-four. Thank you for telling me. We're back in the game. I got it," he said.

It got worse for Johnson from there. He broke a rear end gear in his Chevrolet and went to the garage with 40 laps to go, essentially clinching the championship for Keselowski.

"It all unraveled pretty quick," Johnson conceded.

No longer needing to save fuel, and no longer needing to play it conservatively, he waived off Wolfe's playbook.

"If he's in the garage, let's race," Keselowski said.

That's been Keselowski's attitude since he burst onto the NASCAR scene. He first caught attention as a brash driver for Dale Earnhardt Jr.'s Nationwide Series team, and he was unapologetic for his aggressive driving and his refusal to back down in long-running feuds with established stars Denny Hamlin and Carl Edwards.

But he's been calmer and focused since teaming with Penske in 2009, and his mission has been to give Penske a title. Still, his fame has been for the tweeting, which drew him worldwide attention when he took to Twitter from the cockpit of his car during the red flag in the season-opening Daytona 500.

NASCAR loved the attention it received, but quietly admonished him later for having a phone in his car, which is banned because it can manipulate electronic fuel injection systems. So when he tweeted again last week under red at Phoenix, NASCAR fined him $25,000 — which angered fans who felt a mixed message had been sent.

But Keselowski, who was tweeting into the early morning hours Sunday, handed his phone over with no resistance right before he climbed into the car at Homestead.

The win is the first for Dodge since Richard Petty's Cup title in 1975, and comes as the manufacturer is leaving NASCAR. Penske announced days after the Daytona 500 it will move to Ford next year, and it led to Dodge's decision to pull out of NASCAR.

"Not one failure all year long in that Dodge engine, so I want to thank Dodge for what they've done for us," Penske said after Keselowski secured the title.