Spain's Dani Pedrosa stormed to victory in the shortened Malaysian Motorcycle Grand Prix, keeping his championship title chase alive on a rain-soaked circuit with his sixth win of the year.
The Honda rider passed pole-sitter and Yamaha ace Jorge Lorenzo, who is the championship points leader, midway through a race which saw a raft of riders crashing out.
Organisers put out the red flag on lap 13 of the 20-lap race to stop the event due to the torrential rain.
It is Pedrosa's third successive race win since moving up to the MotoGP class. He won the race in 29 minutes 29.049 seconds while Lorenzo was 3.774 seconds behind.
Pedrosa's Australian teammate Casey Stoner, recovering from an ankle injury, was third after starting from the second row. Stoner clocked in at 29 minutes 36.193 seconds.
With his first ever win in wet conditions, and battling for his first MotoGP crown, Pedrosa _ who started second on the grid _ narrowed the points gap with his countryman Lorenzo, on 321, to just 22.
There are two more races left in the 2012 season, in Australia and Valencia.
Lorenzo charged away from the pack at the start with hopes of winning for the first time in the MotoGP class at Sepang.
But as increasingly heavy rain began to hit the circuit, Pedrosa brilliantly picked up speed and caught his arch-rival.
"It is my first winning in the wet and I am very happy. I could get some rhythm and maintained a constant lap,'' he said.
Lorenzo said the red flag came out just as Pedrosa overtook him.
"I was struggling when heavy rain poured on the track. I am lucky to be second. It (the 20 points obtained for second place) is good for the championship title,'' he said.
Lorenzo has finished second on the last six occasions he has started from pole position. The only race he won from pole in 2012 was the season opener in Qatar.
Stoner, who has 230 points, missed three races this season after injuring his right ankle in qualifying at the Indianapolis Grand Prix. He returned last weekend at Motegi and plans to retire at the end of this season.
Nine-time world champion Valentino Rossi who has had a bad season for Ducati, finished fifth behind his American teammate Nicky Hayden.
Alex De Angelis won the Moto2 race at a rain-soaked circuit, with Australian Anthony West coming second in an action-packed event.
British rider Gino Rea, a successful supermoto rider, was third on a Suter.
Pouring rain cut the 19-lap event to 15 laps after an earlier heavy shower delayed the start of the race.
German KTM rider Sandro Cortese won the Malaysian Motorcycle Grand Prix to be crowned the inaugural Moto3 world champion.