CHESTE, Spain -- Andrea Dovizioso of Ducati took advantage of a difficult wet track to win the season-ending Valencia MotoGP on Sunday.
Poor conditions forced the race to be interrupted near its halfway point with Alex Rins in the lead on a Suzuki, but Dovizioso took control after the restart to seal his fourth win of the season.
The Italian rider, who had already secured second place in the championship, started third at the Ricardo Tormo circuit. He finished ahead of Rins and Pol Espargaro of KTM, who earned the first podium of his career.
Seven-time MotoGP champion Valentino Rossi started near the back but recovered to second place before crashing with five laps to go. He still secured third place in the championship, ahead of teammate Maverick Vinales, the pole-sitter who was one of the many riders to go down before the race was red-flagged because of the treacherous track conditions.
Marquez, who claimed his fifth MotoGP title in Japan three races ago, crashed with 21 laps to go after starting fifth. He competed with pain in his left shoulder after also crashing in qualifying on Saturday.
Andrea Iannone, who is moving from Suzuki to Aprilia next season, also crashed early in the race.
It was the last MotoGP race for Dani Pedrosa, the 33-year-old Spaniard who is retiring as a full-time MotoGP rider and will test with KTM next season. He finished fifth on Sunday.
Three-time champion Jorge Lorenzo ended 12th in his final race before moving from Ducati to Honda to replace Pedrosa.
Alvaro Bautista, the 33-year-old Spaniard who will race in Superbikes next season, also was among the riders who crashed.
Earlier Sunday, Turkish rider Can Oncu won his maiden Moto3 race to become the youngest grand prix winner in motorcycling at age 15.
Oncu secured the historic victory by taking advantage of crashes on a wet track in front of him. He started fourth and moved to third by the end of the first lap, then second-place Marco Bezzecchi crashed early in the race and leader Tony Arbolino went down with 12 laps to go.
Oncu won at 15 years, 115 days, breaking the record held by British rider Scott Redding since 2008. Oncu also became the first rider to win on his grand prix debut since Japan's Noboru Ueda in a 125cc race in 1991.
Portuguese rider Miguel Oliveira won the Moto2 race for his third victory of the year, finishing ahead of Spanish riders Iker Lecuona and Alex Marquez, Marc's younger brother who recovered after crashing while leading the race with 10 laps to go. Francesco Bagnaia, the Moto2 champion in advance, finished 14th.