Following his win at the Dutch MotoGP Yamaha rider Spies is seventh in the drivers' standings [GALLO/GETTY] 

America's Ben Spies crowned Yamaha's 50th anniversary with his first MotoGP victory in Assen on Saturday.

The American, starting in second place in damp conditions, was the first new winner in MotoGP since Italian Andrea Dovizioso in 2009.

Championship leader Casey Stoner took second place to extend his lead to 28 points at the top of the standings.

Spies' Spanish team-mate Jorge Lorenzo, the reigning champion, finished in sixth place after a first-lap collision with Honda rider Marco Simoncelli, who recovered to finish ninth.

Honda's Andrea Dovizioso took third place, ahead of Ducati's seven-time world champion Valentino Rossi, who has finished on the podium just once in the season to date, and American Nicky Hayden (Ducati).

Spies the opportunity 

A chaotic start to the race saw pole-sitter Simoncelli and Lorenzo collide on the third corner after the Italian lost grip of his bike and wiped the defending champion off the track.

Frenchman Randy de Puniet was the next rider to exit the race and Spies, who started on the front row, capitalised on the carnage behind him to pull four seconds clear of Stoner.

Stoner, chasing his fourth successive victory, gradually began to eat into the American's advantage, however, while Dovizioso and Rossi moved into position on the Australian's tail.

The race's closing stages could not match the opening laps for drama though, allowing Spies to pull away from the chasing pack and close out his first ever MotoGP victory in style.

In the Moto2 event, Spain's Marc Marquez recorded his second win to move second in the championship standings. Championship leader Stefan Bradl, who had finished every race in the top five, crashed with only three laps remaining.

The 125cc grand prix was also won by a Spaniard. Teenager Maverick Vinales raced to a controversial victory after the race was red-flagged with 7 laps remaining due to the wet conditions.

Source: Agencies