When the red lights went out, Bayliss lead a Ducati one-two around the first turn (if they don't already have launch control then they won't ever need it), while behind them Hopkins rocketed through from the second row to take third into the first right hander, ahead of Biaggi, Gibernau, Ukawa, Checa, Rossi and Edwards.
Rossi then lost even more ground after almost hitting Ukawa when they both went for the same piece of tarmac, but the Italian more than made up for a mediocre start with a stunning set of opening laps, to take second behind the 'opposite lock' Capirossi by lap 3, then inherited the lead two laps later when Loris ran wide at the final turn.
Home hero Carlos Checa retired on lap four with electrical problems, the Spaniard literally jumping up and down with disgust as his M1 ground to a halt, and the local fans were dealt another blow when an equally distraught Gibernau fell from second on lap 8 after losing the front of his RCV at turn 2. Sete was so upset he almost had to be carried from the gravel trap.
But back up front, Rossi was breaking all opposition with a series of stunning laps, to build a comfortable 6secs margin over Biaggi by the end of the race, while the Ducatis were just beginning their battle for the final podium place.
The ever sideways Capirossi finally gave the position to his team-mate on lap 13 when he was flung from his Desmosedici in a mid turn shower of sparks, leaving Bayliss to ride what would be a lonely race to his first GP podium.
By contrast, the fight for 5th, 6th, 7th and 8th between (respectively) Hopkins, Barros, Ukawa and Tamada would go almost to the flag with position changes at almost every turn.
Of the group, Hopkins and Tamada were probably the most surprising, Hopper being just 19 and mixing it effortlessly with GP winners Barros and Ukawa, while MotoGP rookie Tamada proved his race skills by outbraking Barros, there's not many that can claim to have done that.
By the end of the 27 laps, Ukawa's 2003 spec RCV overcame top Yamaha Barros by just over a second, while 5secs behind Tamada held off Hopkins after both were unable to match their former rivals late race pace, with Hopkins having his hands full keeping a charging Shinya Nakano behind.
Aoki took top two-stroke honours in an excellent ninth – ahead of Jacque, Haga and team-mate McWilliams, while Kenny Roberts was nowhere near the pace of his young team-mate and finished just 13th – 3secs ahead of countryman Edwards.
Pitt won the private battle between the Kawasaki riders to take their first point of the season for 15th, but just 0.1secs ahead of impressive test rider Alex Hoffmann. Melandri rode a strong early race on his belated MotoGP debut, but an off track excursion saw him slip to 17th, ahead of final finisher McCoy, who was a lap down.