LAGUNA SECA, California (AFP) - Jorge Lorenzo took pole position for Sunday's US Grand Prix with a fastest lap of one minute, 21.678 seconds, but ended Saturday's qualifying session with a spectacular spill on which he flipped over his handlebars and landed hard on the track.

Spain's Lorenzo, who is in second place in the MotoGp championship standings, landed on his right shoulder on the track and then slid headfirst about 30 metres in the sand.

He was taken off the track by ambulance. It was not immediately clear how badly he was injured.

His Fiat Yamaha teammate, Valentino Rossi of Italy, claimed second spot on the starting grid with a best lap of 1:21.845 as the hour-long qualifying session ended. Rossi is the championship standings leader after capturing his 100th career victory last week.

Australian Casey Stoner was third fastest Saturday with a lap of 1:21.910 on his Ducati on the 3.61-kilometre (2.243-mile) track. Stoner started from the pole last year at Laguna Seca, but finished second to Rossi in the race.

Stoner also had a scary crash on his final lap, flipping off his bike moments after Lorenzo's crash and landing on the track. He was driven back to his team's garage, and could be seen limping as he got off a cart.