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If his goal was to keep all of NASCAR on its toes during Champion's Week, Brad Keselowski played it perfectly.

He was brash and bold and changed nothing about his personality as he seamlessly navigated press events, cocktail receptions, sponsor dinners and socializing. He burned the candle at both ends in Las Vegas, trying hard to hold his own with veteran drivers who tried but failed to rattle him with some lighthearted hazing.

Keselowski was like the pesky kid brother nobody wanted around, and he seemed to love playing the part.

Until it was time to be the Sprint Cup champion.

Keselowski officially accepted his new title with an unscripted speech that impressed most everyone in the crowd of 1,500 in the ballroom of the Wynn Las Vegas Resort. He refused to write a speech ahead of time, which had NASCAR officials holding their breath for most of the 12 minutes Keselowski spoke.

In going up to the podium with no notes loaded into the TelePrompTer, Keselowski joined Jimmie Johnson as the only two drivers in the last decade to go off-the-cuff in their championship speeches. Johnson only did it once, after his fifth title in 2010.

The highlight of Keselowski's speech was the close, in which it became clear how much he appreciates his new role as champion.

"As we look into `13, I hope as a sport we can continue to find common ground to unify," Keselowski said. "We have some of the smartest people that can solve any problem. As a champion, I want to be your leader, and I want to help you make it happen."

His remarks come with NASCAR down to roughly eight weeks to finalize development on its 2013 car, which the industry is counting on to improve the racing. As attendance and television ratings continue to slip, the actual on-track product is under heavy scrutiny and the garage seems divided as to how it can be improved.

At 28, Keselowski is the eighth-youngest champion in Cup history and he claimed his title in just his third full season. But he grew up in a racing family and has a strong desire to do his part to help motorsports succeed.

And as a driver for Roger Penske, the team owner who is deeply committed to both NASCAR and the struggling IndyCar Series, Keselowski understands the challenges currently facing American auto racing. That's what he meant, he said after Friday night's speech, when he called for unity.

"You look at IndyCar and the things they are fighting, it shows how you can take a series with great action, great people and (throw) it all away when you don't work together," Keselowski said. "I feel like in our series, we have the potential to be stronger than what we are if we work together. I want to be a part of that, to work with others and help move this sport forward and make it as strong as we can be."

It was a humble side of Keselowski that he rarely shows, partly because he likes to be different and enjoys keeping everyone guessing. It's part of a game Keselowski is seemingly playing at times as he tries to beat his competitors both on and off the track.

Three-time champion Tony Stewart seems wise to Keselowski's act, noting in his speech that the late NASCAR spokesman Jim Hunter would have really enjoyed Keselowski if he'd gotten a chance to know the driver. Hunter enjoyed edgy and colorful drivers, and grew close to Stewart at a time when Stewart was sparring with most NASCAR officials.

"I don't think Brad has learned to be cautious yet," Stewart said. "Hopefully that won't bite him like it has a lot of drivers in the past. But it's refreshing. It's nice to see somebody that just speaks from the heart and isn't guarded when he speaks. That's the way all of us should be."

Four-time champion Jeff Gordon agreed Keselowski is a bit of a throwback, and shouldn't change.

"Too polished is sometimes not good, either," Gordon said. "You've got to be who you are and let that shine. That's what I see in him. There doesn't seem like there's much fazing him or changing him, at least not what I've seen so far, so I don't anticipate it happening."

It's worked for Keselowski, who went from a development driver in the Hendrick Motorsports system quickly earning a reputation as a wild child with no regard for others to the top of the sport in a little over three years. He's done it by settling into a home with Penske, learning how to be a team leader and getting comfortable in his own skin.

The payoff was a Nationwide Series championship in 2010 with crew chief Paul Wolfe, the first official NASCAR championship for Penske, and then a long-term contract extension that was announced a year ago for Keselowski and Wolfe.

Then the duo teamed together this season to win five races -- two in the Chase for the Sprint Cup championship -- and bring Penske Racing its first Cup title 40 years after Penske first entered NASCAR. It carried a $5,728,405 bonus from series sponsor Sprint that pushed the No. 2 team's season winnings to $12,106,255.

More importantly, it provided credibility to a voice Keselowski is unafraid to use.

"To see Brad and how he is going to represent the sport probably means the most to me because he's loyal," Penske said. "I think what you see is what you get. He's a high-integrity guy, he's a hard worker and he's a big team player."