BRNO, August 16, 2008 (AFP) - Defending champion Casey Stoner of Australia battled with a mystery illness here on Saturday to claim his sixth successive pole position for Sunday's Czech Republic Grand Prix.

The Ducati rider, who fell ill with fever and cramp during Friday's free practice, posted the fastest time of 2min 11.657sec on the wet Brno circuit, pipping standings leader Valentino Rossi, of Yamaha, by 1.189sec.