Casey Stoner took Ducati's first Mugello victory and ended Valentino Rossi's seven-year run of wins at his home track by beating the two Yamahas to victory in a wet-dry Italian Grand Prix.
Rossi had to settle for third, behind his team-mate Jorge Lorenzo, who took second despite crashing his main bike on the way to the grid and then making a very poor start from pole.
The race began with the track still damp, and Stoner burst into the lead off the line, but only briefly before wet weather specialist Chris Vermeulen thrust his Suzuki to the front.
This pair and Honda's Andrea Dovizioso proceeded to swap the lead through the opening stages, with Rossi lurking close behind and Marco Melandri revelling in the conditions and charging through towards the top five on the Hayate Kawasaki.
Lorenzo recovered from his pre-race error and wheel-spinning start to soon rejoin this pack on his spare bike while Yamaha worked to repair his original machine in time for the bike changes as the weather improved.
Dovizioso managed to get around both Vermeulen and Stoner on lap three, and as the track began to dry, Rossi and the flying Melandri further demoted the Suzuki and Ducati and lined up to challenge Dovizioso for the lead.
Rossi hit the front for the first time on lap nine, with Melandri following him past Dovizioso and the Honda rider diving into the pits for his slick-shod bike just afterwards.
Melandri's charge was not finished, and he brilliantly passed Rossi to take the lead - from 15th on the grid - before they too switched to slicks at the end of lap 10.
Though they rejoined in front, Dovizioso's additional lap on dry tyres paid dividends, and he swept into the lead as his countrymen tried to get their rubber up to temperature.
Melandri soon started falling down the order on the dry track, while Rossi - who had taken a hard slick tyre - was unable to get up to speed as quickly as Stoner and Suzuki's Loris Capirossi, who demoted the Yamahas and set off after Dovizioso.
The Italian had led by three seconds, but soon had both Stoner and Capirossi not only on his tail, but slicing past to push him back to third.
Capirossi, in his best ride since joining Suzuki last year, then attacked Stoner and took the lead of his home race for one glorious lap before the Ducati got back ahead and started edging away.
Both Capirossi and Dovizioso then began fading, and as the Yamahas picked up pace in the closing stages, Lorenzo and Rossi charged back through to second and third. The podium spot - which he hung on to despite a late resurgence from Dovizioso - was scant consolation for Rossi as his remarkable home winning streak ended.
Colin Edwards beat his Tech 3 Yamaha team-mate James Toseland to sixth, the Briton having flown up the order after being the first to gamble on slicks.
Randy de Puniet (LCR Honda) took eighth, followed by a breakthrough performance by Pramac Ducati's Niccolo Canepa, another man to make an early bike swap. Vermeulen and Melandri fell back to 10th and 11th in the dry.
There was more bad news for the injury-blighted Dani Pedrosa (Honda), who crashed heavily before half-distance while running in the midfield and required medical assistance. The Spaniard had already been struggling for fitness this weekend after damaging the muscles in his right hip when his body was jarred while catching a slide in practice.
Pos Rider Bike Time
1. Casey Stoner Ducati 45m41.894s
2. Jorge Lorenzo Yamaha + 1.001s
3. Valentino Rossi Yamaha + 2.076s
4. Andrea Dovizioso Honda + 2.129s
5. Loris Capirossi Suzuki + 3.274s
6. Colin Edwards Tech 3 Yamaha + 24.451s
7. James Toseland Tech 3 Yamaha + 25.621s
8. Randy de Puniet LCR Honda + 26.046s
9. Niccolo Canepa Pramac Ducati + 31.815s
10. Chris Vermeulen Suzuki + 34.814s
11. Marco Melandri Hayate Kawasaki + 35.090s
12. Nicky Hayden Ducati + 39.122s
13. Mika Kallio Pramac Ducati + 52.462s
14. Toni Elias Gresini Honda + 52.478s
15. Alex de Angelis Gresini Honda + 1 lap
Dani Pedrosa Honda 12 laps
Yuki Takahashi Scot Honda 9 laps