Australia\'s freshly crowned world champion Casey Stoner topped the times in the first two free practice sessions on Friday ahead of Sunday\'s season-closing Valencia MotoGP. The Honda rider set the early benchmark with a time of 1min 45.513sec, with team-mate Dani Pedrosa 0.223sec back in second and multiple former champion Valentino Rossi\'s Ducati in third at 0.315sec. In Moto2, Germany\'s Stefan Bradl is poised to take the 2011 title as Spaniard Marc Marquez, the only rider close enough in the standings to deny him the championship, is likely to miss the race. Marquez has suffered from vision problems since falling in testing for last month\'s Malaysia GP and sat out Friday\'s rain-hit practice. Sunday\'s race is being staged in the shadow of Italian former Moto2 champion Marco Simoncelli\'s death a fortnight ago in Sepang.