Jorge Lorenzo, winner here last year before going on to clinch the MotoGP world title, was quickest in US Grand Prix practice Friday to throw down the gauntlet to championship leader Casey Stoner. While Australian Stoner posted the third fastest time after setting the pace at Laguna Seca in the morning, Spaniard Lorenzo eclipsed his rival with a sizzling display on his Yamaha on a sun-baked but breezy afternoon. The 24-year-old from Palma, who is bidding for his third win this season, completed 24 laps on the twisting, technically challenging circuit with a best time of one minute, 22.056 seconds. Spaniard Dani Pedrosa, fresh from victory at last week's German Grand Prix, was next best on 1:22.197 with Honda's Stoner, champion here in 2007, third on 1:22.231. Italian Andrea Dovizioso, also riding a Honda, was fourth on the timesheets with 1:22.537. Lorenzo trails Stoner by 15 points in the overall standings with nine races left, the Australian having been in scintillating form this season with four wins and eight podiums in the first nine races. However, Lorenzo made up some ground on Stoner when he snatched second place for Yamaha at last week's German MotoGP where the pacesetting Australian had to settle for third.