Jorge Lorenzo held off team-mate Valentino Rossi to win an action-packed Japanese Grand Prix at Motegi, the 700th premier-class race to be held since 1949.

Grid positions had been decided by free practice times after a qualifying wash-out, with Sunday's extended morning warm-up then rendered useless - in terms of dry race preparation - by another heavy shower.

That meant riders began the race with only 45 minutes of dry set-up time, from Friday afternoon, under their belts - prompting Rossi to predict that the race would be “the most uncertain ever”.

Rossi made an unusually fast start from pole to lead Chris Vermeulen and Dani Pedrosa - just eleventh on the grid - through turn one, with Qatar winner Casey Stoner dropping from second to fourth ahead of Lorenzo and Andrea Dovizioso.

Pedrosa and Lorenzo overcame Vermeulen's Suzuki on the opening lap, with Jorge then overtaking Pedrosa's Repsol Honda on lap three and instantly biting a half second chunk out of Rossi's lead.

By lap eight of 24 Lorenzo was just 0.2sec behind the leading Fiat Yamaha and ready to strike. The Spaniard's first attempt was unsuccessful, but Rossi was helpless to prevent the #99 from out-braking him at the end of the back straight later on lap nine.

Lorenzo and Rossi remained in close formation until Rossi suffered problems on lap 15, and the resulting 'moments' suddenly handed Lorenzo a 1.5sec lead.

Rossi was now in real danger of losing second to Pedrosa, who had surprised even himself by keeping pace with the leaders despite his diminished physical condition following last month's knee and forearm surgery.

Dani made a lunge for second with eight laps to go, triggering an entertaining series of passes and re-passes between himself and Rossi. The Doctor ultimately prevailed and went on to enjoy a late race resurgence, closing back in on Lorenzo to keep pressure on the 22 year-old.