Casey Stoner may have suffered two costly falls at the past two rounds, but the reigning world champion underlined that his raw speed remains intact by setting the pace in both of Friday's free practice sessions at Misano.

The Ducati Marlboro rider, now 50 points from Valentino Rossi, began another impressive opening day by edging out a surprisingly strong morning lap from Colin Edwards - which the American was unable to replicate in the afternoon - by 0.003secs, with Rossi a 'relaxed' fifth.

Stoner then remained over 0.8secs clear of the competition for much of the afternoon hour, before Rossi halved that margin to 0.418secs on his penultimate lap - by which time Stoner was already sitting in the factory Ducati garage.

Late laps from Loris Capirossi, Randy de Puniet and Chris Vermeulen saw Capirossi claim fourth for Rizla Suzuki, just 0.153secs from Rossi, with de Puniet a welcome fourth for Honda LCR - making him the top Michelin rider - and Vermeulen 0.937secs from fellow Australian Stoner in fifth.

Race winning rookie Jorge Lorenzo was the final rider within one second of Stoner on the Michelin-shod Fiat Yamaha, with home star Alex de Angelis seventh for Honda Gresini.

Edwards was eighth quickest for Tech 3 Yamaha during the afternoon, with Shinya Nakano ninth at the start of his second race weekend with a factory spec Honda, while rookie James Toseland completed the top ten.

Michelin, under immense pressure to deliver competitive tyres after three tough events, put an encouraging five riders inside the top ten this morning, although things swung in Bridgestone's favour this afternoon with a 6-4 split.

Repsol Honda, the only factory team with both riders on Michelin tyres, had a notably tough day with third in the championship Dani Pedrosa - who publically blasted Michelin after a frustrating 15th at Brno and appears to be pushing for a Bridgestone switch - just 14th and twelfth.

The Spaniard, a double race winner in 2008, also still appears to be struggling with his hand injury, while returning team-mate Nicky Hayden - having been a promising sixth this morning - fell at the final turn of his final lap this afternoon. The American, who missed Brno due to a heel injury, finished the day one place in front of Dani.

Satellite Honda rider Andrea Dovizioso was forced to settle for a lower than usual 13th during the start of his second MotoGP event on Italian soil, while Alice Ducati riders Toni Elias and Sylvain Guintoli were an evenly matched 14th and 15th.

Both were nevertheless comfortably clear of the factory Ducati of Marco Melandri, who looks set for another tough weekend, as does Anthony West - who was over one-second slower than Melandri to be left 17th and last on the lone Kawasaki.

West joined Edwards in lapping slower this afternoon, while team-mate John Hopkins didn't take to the track at all on Friday, due to pain from a rib injury sustained last time out at Brno.

Friday practice (2):

1. Stoner
2. Rossi
3. Capirossi
4. de Puniet
5. Vermeulen
6. Lorenzo
7. de Angelis
8. Edwards
9. Nakano
10. Toseland
11. Hayden
12. Pedrosa
13. Dovizioso
14. Elias
15. Guintoli
16. Melandri
17. West