Casey Stoner has won his second MotoGP title, in front of his home fans and on his 26th birthday, with his fifth consecutive victory at Phillip Island in Australia.

Stoner, who needed only a top six finish following the last-minute withdraw of Yamaha's Jorge Lorenzo due to a nasty finger injury in warm-up, suffered a late scare when a rain shower descended on the circuit.

But Stoner held his nerve to win by 2.210sec over Marco Simoncelli and become Honda's first MotoGP champion since Nicky Hayden in 2006.

"I don't think I could fit any more things into today - it's my birthday, my fifth win, my home track and my second world title!" smiled Stoner.

"To win like this is really something special; words can't describe it. It's been pretty much a perfect season for us, and a big thank you to the team and to everyone.

"This weekend's been great for us, but the race threw a few curve balls. They were very, very tricky conditions and there were a few heart-in-mouth moments!

"I wanted to win this one. Not too many people have so many things align in one day and it's hard to get a hold of it. Maybe it was just meant to be, but it's something unbelievable."

Stoner's victory also handed Honda the 2011 MotoGP Constructors' title, with two rounds still remaining.

After joining MotoGP with LCR Honda in 2006, Stoner switched to the factory Ducati team the following year - with instant title success.

Stoner won 23 times for the Italian factory between 2007-2010, before joining Repsol Honda this season. The Australian has won 9 of the 16 rounds so far.