Australia’s Casey Stoner beat newly crowned world champion Jorge Lorenzo of Spain by almost nine seconds Sunday to claim his fourth straight Australian Motorcycle Grand Prix.

Stoner, who turned 25 on Saturday, started from pole position after dominating qualifying and rode his Ducati to an 8.598 second win over Yamaha’s Lorenzo, while Italy’s seven-time world champion Valentino Rossi, also on a Yamaha, finished third.

“When I won it twice in a row and was going for the third, nobody was really expecting it but of course they were going to enjoy it,” Stoner said. “But this year everybody seemed to really expect it and they weren’t going to take any other result.”

Stoner gave his home fans no nervous moments in a pole to post win. He reached the first corner of the Phillip Island circuit in the lead and had opened a 1.5-second edge over Lorenzo by the end of the first lap.

He steadily stretched his advantage and by the race’s halfway point held a 3.5 second lead over the Yamaha rider who started from second on the grid.

Lorenzo said he had been optimistic of catching Stoner early after Sunday’s warm up lap.

“In the warm up lap I looked to my left and I saw the rear tire of Casey’s was new, so I though maybe in the first or second lap he will be very, very careful,” he said.

“But it was the opposite. He was so, so fast and in the first lap he had a gap of one-and-a-half seconds. I tried my best but from the middle of the race he was going faster and faster and I couldn’t make it.”

Rossi, who started eighth, briefly slipped back a place but recovered to sixth by lap six. He then overtook Americans Nicky Hayden and Ben Spies to sit in third place by lap eight.

Hayden reclaimed third place on the second to last lap, but Rossi fought back to gain a place on the podium with a desperate late surge. Hayden finished fourth on a Ducati, 18.035 seconds behind Stoner, while Spies, Lorenzo’s Yamaha teammate, was fifth.

Stoner made a slow start to the 2010 season but has now won three of the past four races, missing a clean sweep when he crashed at Malaysia last week.

He can still finish second behind Lorenzo on the world standings with two races to go. With his 25 points from Sunday’s win, he lies 22 points behind Honda’s Dani Pedrosa who has missed the last three races with injury.

“Every weekend, these last four especially, we’ve been trying to win and we’ve managed to win three out of the last four,” Stoner said. “Unfortunately last week (in Malaysia) I slipped off on the first lap with a bit of a misjudgment.”

Pedrosa took part in qualifying in Australia, but pulled out of Sunday’s race because of continued problems with his recovery from a broken collarbone. Suzuki’s Loris Capirossi also withdrew because of injuries suffered in a high speed crash in Saturday’s qualifying.

The MotoGP season concludes with races in Portugal in two weeks and in Valencia, Spain.

Stoner was having what may be his last ride on a Ducati in his home country before joining Honda for the 2011 season.

Spain’s Marc Marquez stretched his championship lead when he won his ninth race of the season in the 125cc class, beating compatriots compatriot Pol Espargaro with Nicolas Terol.

San Marino rider Alex DeAngelis won the Moto2 Grand Prix, beating Briton Scott Redding and Italian Andrea Iannone, but Toni Elias of Spain had already sealed the world title.

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