MADRID (AP) - Sebastian Vettel ensured Red Bull's place in Formula One history as the sport's youngest ever champion in a season that featured one of the most competitive grids in history and Michael Schumacher's disappointing return.

The 23-year-old Vettel won the last two races of the season to overtake two-time champion Fernando Alonso for the title in Abu Dhabi.

Seven-time champion Schumacher, meanwhile, returned with Mercedes after a three-year retirement at age 41 and finished 184 points behind Vettel in ninth.

Red Bull delivered a jolt to F1 as Vettel teammate Mark Webber finished third overall to ensure the constructors' championship for the energy-drink backed team.

After only six seasons in F1 and after nearly breaking through with the title the previous season, Red Bull expects more of the same in 2011.

"We expect a new car again but we don't take anything for granted," said Webber, who finished the last four races with a fractured shoulder to end 14 points behind.

The Australian has cleared the air with Vettel after a season when the two drivers clashed on the track, a year in which four champions raced in one of the most competitive seasons in history.

With Vettel, there will now be five champions on the grid for the start of the 2011 season.

Red Bull said it will not alter its ban on team orders, although FIA has decided to allow them as long as they don't bring the sport into disrepute.

Ferrari president Luca di Montezemolo said Alonso and teammate Felipe Massa will start on equal footing.

"In a year when we did not have the best car, we managed to get to the last race still in with a great chance of winning the title after staging a really strong recovery," said Alonso, who went into the finale at Abu Dhabi with an eight-point lead but ended up four point behind Vettel in second.

"In a race like that last one, anything could happen."

Neither Lewis Hamilton nor Jenson Button managed to secure the championship for McLaren, but all teams expect the British team to be one of the title favorites despite the ban on F-ducts and adjustable rear wings, two technical advantages McLaren held over the field.

Button, who finished fifth behind Hamilton after winning his first title in 2009, expects the team to again push the boundaries of the new regulations, including the return of overtaking system KERS.

"They have so much experience in that area that I think we'll have an advantage," Button said. "We'll have an advantage on Red Bull and Ferrari I think, which is great. We'll take every advantage we possibly can."

Red Bull has no experience with KERS, while Ferrari does. Mercedes is hoping its engine compatibility with the energy recovery system gives it a chance to challenge after Schumacher's return fizzled.

Schumacher and the Silver Arrow's optimistic return quickly faded. Teammate Nico Rosberg nearly doubled Schumacher's point total, but still finished seventh.

Renault, meanwhile, showed it was making strides to move past the "crashgate" scandal of 2008. With Robert Kubica at the helm and a first Russian driver in Vitaly Petrov, the French team finished fifth. It will start 2011 as Team Renault Lotus after reaching an agreement to use the iconic team name.

The move means Malaysia Air boss Tony Fernandes may have to find a new name for his cars after he returned the Lotus name to F1 in 2010. Lotus proved to be the best of the three new teams, ahead of Virgin Racing and HRT.

Several regulation changes will greet teams in 2011 as drivers face tougher sanctions for dangerous or unsporting driving, with stewards able to exclude them from a race or suspend them for the next. F1 will also introduce a curfew to cut down on man hours. Mexican driver Sergio Lopez and Pastor Maldonado of Venezuela bring a Latin American flair to the grid in 2011.

And a street mugging in central London will not keep 80-year-old F1 boss Bernie Ecclestone away as the sport survived the season with all major sponsors intact, a successful first South Korean GP and a season free of lurid off-circuit scandals.

BRISBANE, Australia (AP) - American tennis star Andy Roddick says he feels fit for the first time in more than six months after winning his battle against the strength-sapping illness mononucleosis.

World No. 8 Roddick said he fought against the illness for most of last year when he failed to reach the quarterfinals at Wimbledon and the French and U.S. Opens.

He said on Wednesday he had worked hard to regain his fitness during the recent offseason and would look to next week's Brisbane Invitational tournament as a springboard into a better 2011.

"For me it's just a matter of getting right, getting healthy," Roddick said. "I battled sickness for a big part of last year and from there I just felt like I was playing catch-up.

"You train hard and you get hurt in training coming back. You don't train, you rest and you try and come back and your body is not right and it shows.

A former world No.1, Roddick's ranking dropped as low as 13 in August last year before getting back into single figures, but he now felt ready to push for the world's top five.

"It's the first time I've felt right since last May so when you are fit it takes a lot of the mental pressure off," Roddick said.

"You feel like you can play any way you want so I feel fresh and I feel enthused and ready."

Roddick beat Czech Radek Stepanek to win last year's final at Brisbane and said he was looking to the Jan. 2 to 9 tournament for a similar show of early season form as he builds up for next month's Australian Open.

"I came in last year and hadn't been playing much so this was a really good springboard into the year for me," he said.

"I like being in the same country but also I like this event. My wife enjoys coming here so let's not pretend I make any decisions."

Roddick is second seed for Brisbane, behind world No.4 Robin Soderling of Sweden.