Jorge Lorenzo mastered the rain-soaked Le Mans track to win the French Grand Prix for the third time on Sunday, with seven-time world champion Valentino Rossi overtaking Casey Stoner late on to take second place.
The Spaniard, who won here in 2009 and 2010, put in a masterful performance as he surged ahead from fourth place on the grid to beat Rossi by nearly 10 seconds and regain the overall lead from defending champion Stoner.
"Winning in France is fantastic. I kept my concentration because the turns were very slippery,'' Lorenzo said.
"It was great to see all the fans here.''
Rossi and Stoner, who will retire at the end of the season, were locked in a frantic battle for second in the pouring rain, with the Italian overtaking the Australian on the final lap to improve on his third-place finish last year.
"I wanted to do better than last year, so I tried to stay calm and then I pushed hard,'' Rossi said.
"I'm happy for all my team at Ducati to be on the podium.''
Spaniard Dani Pedrosa finished fourth after starting from pole position.
In the overall standings, Lorenzo has 90 points after four races, with Stoner on 82 and Pedrosa third on 65. Rossi is sixth.
Pedrosa started poorly, with Stoner, last year's winner in Le Mans, and Rossi pushing his Ducati hard. With the pouring rain pounding the Le Mans circuit, Lorenzo's Yamaha moved to the front.
Pedrosa was clearly struggling to keep his Honda on a clean racing line in the slick conditions, and Rossi and Stoner soon overtook him as they chased Lorenzo.
"The track conditions changed a little and I couldn't find anything more. I did all I could"
Halfway through the 28-lap race, Honda rider Stoner had cut Lorenzo's lead to 2.7 seconds.
"I tried to catch Jorge and went at a little higher pace than him, but unfortunately I think we took too much damage on the tires,'' Stoner said.
"The track conditions changed a little and I couldn't find anything more. I did all I could.''
A couple of lightning-quick laps from Lorenzo saw him pull six seconds clear of Stoner with nine laps to go, while Andrea Dovizioso was locked in an intense scrap with countryman Rossi before drifting out to seventh place.
British rider Cal Crutchlow moved up to fifth, but came spinning off his Yamaha as he misjudged a chicane and finished eighth.
Rossi found a late burst of speed to record the day's fastest lap of 1 minute 44.614 seconds and was right on Stoner's wheel with four laps remaining before cutting inside to pass him on the next lap.
Stoner fought back and overtook Rossi, but the Italian passed him again on the final lap and drew loud cheers from the 80,000 fans braving the downpour.
Stoner had his mind set on victory in his last ever French GP.
"I still wanted to win the race today, and at the beginning of the race the bike was quite nervous,'' he said.
"The front feeling was good but at the rear we had nothing. Dani had the same problems. We lost a lot of time in the beginning.''
The treacherous conditions did some damage.
Randy de Puniet came off his bike straight away, falling back and landing heavily. The Frenchman got straight back up and continued but pulled out after six laps. Spaniard Ivan Silva was also unseated early on and finished 18th.
Meanwhile, Swiss rider Thomas Luthi clinched his first victory of the season in the Moto2 race, comfortably beating Italian Claudio Corti and Britain's Scott Redding.
Frenchman Louis Rossi thrilled home fans with his first career win in the Moto3 category, with Spanish pair Alberto Moncayo and Alex Rins in second and third place, respectively.