The Australian Repsol Honda rider had to switch to his reserve bike after running off into the gravel at the track in north-eastern Spain, before clocking a time of one minute 48.451 seconds, 0.296 seconds quicker than teammate Dani Pedrosa.

American Yamaha rider Ben Spies was third fastest, 0.704 seconds behind Stoner, with champion Jorge Lorenzo, also of Yamaha, fourth with a deficit of 0.819.

With 13 of 18 races completed, 2007 champion Stoner tops the standings with 259 points, Lorenzo has 224 and Italian Honda rider Andrea Dovizioso 185. Pedrosa, who has struggled with a series of collarbone injuries, is fourth on 150.