Valentino Rossi broke Giacomo Agostini's all-time premier-class win record by claiming his 69th MotoGP victory during atrocious weather conditions at the inaugural Indianapolis Grand Prix on Sunday.

The remnants of Hurricane Ike had been battering the circuit since lunch time, when heavy rain and winds hit the Indiana venue, forcing Race Direction to postpone the preceding 250 race.

However, a break in the storm allowed the MotoGP race to start at its allotted time, albeit on a soaking wet track, and it didn't take long for the torrential rain and gusting winds to return...

Rossi dropped from pole to fourth at the start of the planned 28 laps, then surrendered another place to Fiat Yamaha team-mate Jorge Lorenzo. Thereafter, Rossi found his rhythm and made his way back past reigning world champion Casey Stoner, Lorenzo and Andrea Dovizioso to sit second behind home hero Nicky Hayden by lap six.

Passing Hayden was no mean feat and it took Rossi eight laps to finally overtake the late-braking American, whose Repsol Honda seemed to have the edge on Rossi's M1 along the straights.

"It was an amazing race and a great battle with Nicky," said Rossi. "I always enjoy racing with Nicky and it was like three, four years ago when we did a lot of great battles.

"Nicky grew up very close to me because his first year [in MotoGP] was as my team-mate at Honda. I remember him coming first time from the US, and he was very desperate. I say Nicky, Nicky, quiet, quiet!" smiled Rossi. "It is a bit different here compared to US. But he is always strong and hard to overtake because he is very strong in braking.

"So we stayed together very close for many laps. Nicky is very wide, very aggressive but also very clean. So I enjoyed the fight. Then, when I got in front of him, I was a bit faster."

But Hurricane Ike wasn't finished with Indianapolis and on lap 16 of 28 it started to rain heavily once again, accompanied by strong gusts of wind which made riding perilous - even for a seven time world champion.

"I think those were the worst conditions in which I have raced in my career," declared Rossi. "It started to rain strong, so the amount of water went up on the racetrack and it became all dark like in the night, but the biggest problem was the wind. Beer cans and bags [were blown] in front of the bike. It was very, very bad, especially because the wind was so inconsistent and very strong.

"You never knew what would happen," he continued. "Along the straight you used all the width from left to right just to try to go straight! Also, on the exit of turn nine, I had a wheelie and got blown a bit wide, I crossed the white line and lost control of the bike. I was quite lucky.

"Seriously, I think I have to raise my hand [to try to stop the race], but I was in front and could see that my advantage was going up. So I try to go and every lap I wait for the red flag, red flag, and after the red flag arrive I think is the right decision because racing like this is too dangerous."

The race was eventually red-flagged after 20 laps and, following ten minutes confusion as to whether there would be a restart - during which an airfence, amongst other things, was seen being blown in the air - Rossi was confirmed as the first ever MotoGP winner at the Brickyard.

"In my mind, no way to restart, especially because the wind remained very strong," said Rossi. "A restart for eight laps, with all riders together in these conditions is like when you put one bullet in the gun and you make, "trrrrr," like this. It was dangerous; I think it was the right decision."

Rossi was thus confirmed as winning his fourth grand prix in a row and the first motorcycle race held at Indianapolis Motor Speedway since 1909.

"This is fantastic because it's been a long time since I won in the rain and even longer since I won four in a row!" smiled Valentino, who dedicated the victory to his Grandfather Dario, who died on Sunday at the age of 82. "To win the first [MotoGP] race here at Indianapolis is a great emotion. I'm the first motorcycle winner here in 100 years. It is quite special. I like the track, and I think in the next years we can make it even better."

Agostini's record of 68 premier-class wins had stood unbeaten for more than 30 years - and Rossi's hopes his name will stay on top just as long.

"To beat Agostini's record is incredible. 69 is a great number because it means a long time at the top, but I want to try to make a better number," he said. "I don't want to say [Agostini] was my hero because I don't remember Ago race, just 20 years later on television, but he was the number one - well, some people say it is Agostini, some people say Mike Hailwood.

"But anyway, Ago has some other records like 122 victories and especially 15 world championships that for me maybe is impossible, but to beat him in the number of race wins in the premier class is great. I hope my record remains for another 30 years!"

Of more immediate interest to Rossi is his 87 point lead over nearest title rival Stoner, who finished fourth on Sunday, which means The Doctor can win his sixth MotoGP title - and first since 2005 - by finishing fourth or higher next time out at Motegi.

"Now we have an 87-point advantage, and we have the first match point in Motegi in two weeks. In 2005, I have the match point in Motegi for the championship, but unfortunately I make a mistake and take out Melandri and we crash. So I have a bad memory of this," Rossi said. "But this time I am able to finish behind Stoner and lose 11 points. So it is important and also because we lose the championship last year in Motegi. So it is good, and we will try for sure."

Meanwhile, during Thurday's pre-event press conference, Rossi had backed up Colin Edwards' idea of the Indy MotoGP winner running naked along the main straight - but the closest Rossi actually got to publically disrobing was when he gave his jacket to a soaking wet podium girl.

"That idea was from Colin, I remember!" he smiled. "Then on Friday night they say to me maybe it's better for everybody that if I win my umbrella girl get naked on the straight instead..."