Rossi wins twice on 'greatest day'.

Home hero Valentino Rossi beat his MotoGP rivals not once, but twice, to claim a nail biting Italian GP victory in 'one of the greatest days of his life'.

Four riders fought it out in the early stages of race one: Yamaha mounted Rossi and the three Hondas of Max Biaggi, Makoto Tamada - on Bridgestone tyres - and Sete Gibernau.

After battling with Biaggi in the opening laps, Rossi came under determined attack from Tamada, with the pair exchanging the lead no less than five times on lap seven alone.

The action was then interrupted in shocking fashion when Kawasaki's Shinya Nakano suffered a huge fall on the start/finish straight when his rear tyre failed on lap 13... and one lap later Tamada was forced to retire when he felt vibration from his rear tyre and wisely pulled off the track.

Gibernau and Rossi then slugged it out at the front, while Biaggi gradually lost touch. The Rossi versus Gibernau battle intensified on lap 17 when the two riders touched. Everything looked set for an epic contest until a rain shower spoiled the show.

But the restarted 6-lap race proved every bit as entertaining as the remaining 15 riders sped into a wet turn one knowing that places lost early on in a six-lap sprint would prove very difficult to get back. Norick Abe led the charge with Biaggi, Alex Barros and Gibernau in close pursuit.

There were some early showings from unlikely candidates in the first three laps, Troy Bayliss and Ruben Xaus featured at the front for Ducati, but as the last two laps loomed, the first race front runners began to show their form again and come through the field.

With treacherous conditions to deal with Rossi ultimately outran wet weather specialist Gibernau and countryman Biaggi in what proved to be a sprint of high risk and changeable traction.

"Perhaps that was my greatest ever grand prix victory on one of the greatest days of my life," said Rossi after singing the Italian national anthem with thousands of his fans.

"To win in front of all these people is incredible - the only time I have ever seen anything like it was when Ferrari scored a 1-2 at Imola. It's hard to explain the emotion I felt when I heard the crowds cheering for me on the last few laps. I need to say thank you to all of them.

"It was like winning twice today," continued the home hero. "The first one was in the dry, where it seemed like I made thirty or forty overtaking manoeuvres! Every lap there was a fantastic battle with Sete, Max and Tamada.

"It would have been difficult to win in the dry with Gibernau, but the new race in the rain was held in incredible conditions. To run with a slick on a wet track was very strange at the beginning, but fortunately it stopped raining and it was possible to push to the win," concluded the five times world champion.

"That was a really strange day but what a result!" added team director Davide Brivio. "Valentino and the team worked so well to come out on top from the restart in such difficult conditions. I think we will all remember this race for a very long time."

With his second Yamaha victory, Rossi now sits second in the championship on 76 points, ten behind leader Gibernau and four ahead of Biaggi.