On a drying track, he came from nearly a whole lap down to win at the final corner at the notoriously slippery Donington Park circuit.
On Saturday, Alex Barros had grabbed pole position - his third of the year and a strong showing after winning last time out in the Netherlands.
Behind him was championship leader Kenny Roberts Jr. in second, Garry McCoy in third and rookie Valentino Rossi in fourth.
[4][5] The second row of the grid consisted out of Max Biaggi, Carlos Checa, Norick Abe and last year's champion Àlex Crivillé in fifth, sixth, seventh and eighth places.
Aprilia rider Jeremy McWilliams started way down in fifteenth place, failing to improve his time after he broke two bones in his foot after crashing during free practice on Friday.
As the lights go out, Rossi has a bad start when his rear tyre slides, lacking grip because of the wet track on the opening lap.
[8] Rossi behind has managed to pass Jurgen van den Goorbergh and is now battling José Luis Cardoso for eleventh at Starkey's Straight.
At the front, Abe is trying to pass Gibernau around the outside of the entrance at The Esses (Turn 9), but goes a bit wide when he doesn't manage to break properly because of the wet circuit and slots back behind the Spaniard.
As lap two begins, the top six is as follows: Laconi, Barros, Gibernau, Abe, McWilliams and Roberts Jr. Rossi moved up into tenth after passing Tetsuya Harada's Aprilia and Biaggi slid further down the order, now being behind McCoy in a lowly seventeenth spot.
Barros is slowly closing up on Laconi, with Rossi passing Okada at the short straight before Coppice for ninth.
Lap six begins and the top six now consists out of Barros, Laconi, Gibernau, Abe, Roberts Jr. and McWilliams, with Rossi closing up fast.
McWilliams also tries to take Gibernau's fifth place around the outside of the hairpin, touching and making them both lose momentum as they exit the corner.
Coming down into the Melbourne Hairpin, Rossi makes his move and passes Laconi for fifth place by going up his inside, but he runs wide and has to slot back behind the Frenchman as they exit the corner.
As lap nine begins, the top three - consisting of Barros, Abe and Roberts Jr. - now have a significant gap back to McWilliams and behind him, Rossi.
As lap thirteen begins, Rossi immediately is eyeing Abe's fourth position, and makes a successful move on him at Redgate by diving down the inside.
He had a slight moment, causing him to highside just as he wanted to exit out of the Goddards hairpin, throwing him onto the grass at low speed.
At the front, the battle for victory has been reduced to three after the crash of Aoki caused a massive gap to number four Abe, consisting out of Roberts Jr., Rossi and McWilliams.
He surprises Rossi by going up his inside at the beginning of Coppice to move up into second position, also allowing Roberts Jr. some slight breathing room.
McWilliams is now all over the back of the American, lines up a pass at the Craner Curves and overtakes him at the Old Hairpin, taking over the lead under loud cheering from the British crowd.
At Coppice, both Rossi and Roberts Jr. have moments as they exit the corner, showing that they too are starting to have some real tyre problems.
As lap twentyseven begins, Rossi is still right behind McWilliams, who himself is being chased by Roberts Jr. A big part of the circuit has now dried up, making the riders wobble frequently.
Coming up to the Melbourne Hairpin, he finally decides to take the lead by diving down the inside of McWilliams' Aprilia, outbreaking him and finalising the move exiting the corner.
[7] Lap twenty-eight and Roberts Jr. tries to pass McWilliams going into Redgate but misses the speed and almost collides with the rear tyre of the Northern Irishman, forcing him to stay right behind him for now.
[9] Further back, Capirossi comes home in fourth, Dutchman van den Goorbergh in fifth and Abe in sixth.
The Italian national anthem plays and after it is done, the podium girls put wreaths around the necks of the trio and give them all a kiss on the cheek.
The race was not so much fun, with the rear wheel spinning all the time, but my rhythm was not too bad and I was able to get past Barros and Abe before getting up to the lead.