Italy‘s Valentino Rossi sealed his second successive MotoGP world championship on Sunday after finishing third at the Malaysian Grand Prix.

The championship was Rossi’s fourth for Yamaha and his seventh premier class world title overall.

Ducati rider Casey Stoner made light of wet conditions at the Sepang circuit in Malaysia, snatching the lead from Dani Pedrosa on the first lap and then powering away from the Spaniard.

Pedrosa finished in second place while Jorge Lorenzo, the only rider who had any hope of catching Rossi in the title race, finished fourth.

Needing only a top four finish to seal the title, Rossi’s title hopes were further bolstered when Spaniard Lorenzo was penalised for failing to take his starting position on time and made to start at the back of the grid.

Lorenzo, who had qualified second behind Rossi, battled his way up the order but his efforts came to nothing as Rossi settled after an early error and came home safely to win the title.

“It was a difficult year. This race reflected how the season went – very tough, with some mistakes, some disappointing results,” Rossi said.

“But I won six races, I was consistent and it’s another world championship. I thank all the team and everyone who’s helped me.”

Rossi has an insurmountable 286 points in the world title standings with Lorenzo on 245 and Stoner on 220 with the final race taking place in Valencia, Spain next month.

Honda rider Hiroshi Aoyama earlier celebrated his 28th birthday in style with victory in the 250cc category ahead of second-placed Spaniard Hector Barbera and Italian champion Marco Simoncelli.

Aoyama holds a comfortable 21-point lead over Simoncelli going into the last race in Valencia.

Aprilia rider Julian Simon of Spain, who secured the championship with victory at the Australian Grand Prix last week, held off British team-mate Bradley Smith to win the 125cc category. Derbi-riding Spaniard Pol Espargaro took third.

ROSSI FACTS

Born: February 16, 1979, in Urbino, Italy.

* His first passion was go-karts but follows his father Graziano by taking up motorcycling and races in his first grand prix with Aprilia in 1996 in the 125cc category.

* Wins the 125cc world championship in 1997

* Moves up to the 250cc category and seals world championship in 1999 with Aprilia.

* Takes the 500cc world title with Honda in 2001 before winning the 2002 and 2003 championships as the event becomes MotoGP.

* Switches to Yamaha and secures the 2004 and 2005 world titles to become one of the sport’s all time greats.

* Suffers disappointing 2006 and 2007 seasons but pledges to stick with Yamaha and his decision is justified when he surges to the 2008 championship.

* Successfully defends his title with a race to spare in the 2009 season, sealing the championship with a podium finish in wet conditions at the Malaysian Grand Prix.

* Nicknamed “the Doctor” in Italy, he has become one of the country’s most loved sportsmen despite a tax evasion probe in 2007 that resulted in him paying a 35 million euro bill.

* Known for his colourful helmets, Rossi has also shown an interest in Formula One and rallying. He has competed in one-off races in the World Rally Championship and is due to drive a Ford Focus in March’s Mexico rally.

Final 2009 season standings:

1. Valentino Rossi       286.0

2 Jorge Lorenzo            245.0

3 Casey Stoner          220.0

4 Daniel Pedrosa         209.0

5 Andrea Dovizioso      152.0

6 Colin Edwards          148.0

7 Marco Melandri         108.0

8 Loris Capirossi         108.0

9 Toni Elias                         105.0

10 Alex De Angelis      105.0

11 Chris Vermeulen     105.0

12 Randy De Puniet     101.0

13 Nicky Hayden           93.0

14 James Toseland      88.0

15 Mika Kallio              64.0

16 Niccolo Canepa       38.0

17 Gabor Talmacsi       19.0

18 Aleix Espargaro       13.0

19 Sete Gibernau          12.0

20 Yuki Takahashi         9.0