Barros wins first ever 'flag-to-flag', Sete falls.

History was made at today's Portuguese Grand Prix as Camel Honda's Alex Barros completed a perfect weekend by winning the first ever 'flag-to-flag' MotoGP race, after intermittent rain showers which would previously have seen the race stopped instead saw racing continue - and early leader Sete Gibernau would become the first victim of the new rule.

A wet morning warm-up had seen Barros continue his 100% record of leading all five on track sessions heading into the race. The #4 lapping 15secs slower than his pole time to beat Movistar Honda rider Marco Melandri by 0.03secs, while the Italian's team-mate Gibernau took third, a further 0.5sesc behind, with Repsol Honda's Max Biaggi fourth (+0.9secs) and Valentino Rossi fifth (+1.1secs).

There had been no further rain as such since warm-up, but the track still contained a few damp patches as the 19-rider field - Konica Minolta Honda rider Makoto Tamada didn't race today due to the wrist injury sustained during qualifying - lined up on the grid, led by a front row of Barros, Gibernau and Carlos Checa.

Meanwhile, the dense covering of threatening cloud was throwing the odd spot of drizzle just to keep teams and riders guessing.

When the green lights went out it was Checa who looked likely to grab the holeshot, but Gibernau was braver on the brakes and took the lead around turn one, followed by the Ducati rider, then Rossi and Biaggi. Rossi would then dive for second under Checa at turn two, but ran wide and allowed Biaggi ahead.

By contrast, Gibernau had set off like a rocket and by the end of the first lap held a 1.7secs lead over Biaggi, with Barros now up to third ahead of Rossi, Melandri, Edwards, a fast starting Hopkins, Checa, Bayliss, Hayden, Nakano, Capirossi, Xaus, Rolfo, Elias, Roberts and Ellison.

Gibernau aside, man on the move in the early laps was Barros, who graduated to second by outbraking Biaggi into turn one on lap two, and then set off after the Catalan ahead. Biaggi - riding his spare bike after a last minute problem with his preferred machine - couldn't match the Brazilian and instead soon found himself defending third against arch rival Rossi.

Rossi would take the position from him one lap later by replicating Barros' move but, unlike Alex, the world champion couldn't pull away from the Repsol Honda and the pair would remain locked together for almost the entire race.

Meanwhile, Barros had been able to close down Gibernau's lead to around one-second before hitting an 'invisible wall' that prevented further gains, while history would be made on lap 8 as white flags began being waved at the marshal posts - signalling the first ever 'flag-to-flag' rain race.

However, there had been no real increase in the occasional drop of rain that was falling and so no rider took the opportunity to pit for a spare bike... but 8 laps later the rain suddenly increased around turn one - race leader Gibernau was the first to find it and spiralled out of the lead after losing the front even before reaching the apex.

The Spaniard ran to his toppled machine but it was dead, prompting screams of frustration from within the watching Movistar pits and leaving the already injured #15 to walk away with his head shaking in disbelief. All that effort for nothing. But Sete wasn't the only victim as Hopkins fell from a fighting eighth place soon after, almost certainly for the same rain related reason.

Previously, the race would almost certainly have been stopped by either race control or the riders themselves, and then restarted using the order from the end of the previous lap - allowing both Gibernau and Hopkins back in.

But that is the past and Gibernau's demise handed Barros a safe lead, which he would increase to seven-seconds over the battling Rossi and Biaggi with 8 laps to go, by which time the rain had eased off once again. Meanwhile, Edwards and Melandri were still fighting over what was now fourth - and had now been caught by Checa.

Then, with just five laps to go, the drama went up a notch once more as the rain began falling heavier than ever - and again nobody dared pit because the 40ish seconds lost changing bikes just wouldn't be recovered before the finish, despite lap times dropping by around 7-10secs.

Edwards was the first to fall in the 'second' shower, but remounted quickly to only lose two places (to Melandri and Checa) while Rossi just clung on to the other factory M1 after almost losing the front.

Meanwhile, Barros rode though it all as if on rails - but had clearly eased his pace and with two laps to go his lead over a charging Rossi had dropped to 5.5secs.

Alex began his last lap with Rossi visibly closing but, despite a brief wet white line scare, the jubilant Brazilian went on to end his two-year plus win drought by 2.7secs over the Italian superstar, while Biaggi cruised to third a further 3secs back for his first factory Honda podium.

It was literally a perfect weekend for Barros, who should have been competing at his home event had Rio not been cancelled. Nevertheless, he could hardly have asked for more; leading all six on-track sessions to claim his first win since Valencia 2002, when he was also riding for the Honda Pons squad.

29-seconds behind Barros, Melandri and Checa duelled right to the flag, with Checa trying a last lap outbraking move but running wide and allowing Marco to follow up his Jerez third with an Estoril fourth. Edwards would cross the line 14secs behind the pair for sixth, while Hayden, Nakano, Capirossi and Xaus completed the top ten.

Barros' team-mate Troy Bayliss took eleventh after suffering a fall, the Australian crossing the line a fraction ahead of Suzuki's Kenny Roberts, MotoGP rookies Roby Rolfo and Toni Elias, plus WCM's James Ellison - who took the final point.

Shane Byrne was forced to pit even before the race had begun after technical problems with his Team Roberts KTM, but returned to gather further 'test' data for the new machine and was the last rider to finish, in 16th.

Full results to follow...

Portuguese Grand Prix:

1. Barros
2. Rossi
3. Biaggi
4. Melandri
5. Checa
6. Edwards
7. Hayden
8. Nakano
9. Capirossi
10. Xaus
11. Bayliss
12. Roberts
13. Rolfo
14. Elias
15. Ellison
16. Byrne