Rossi beats Stoner in first Brno practice

In the end, Rossi's Yamaha proved marginally faster with a lap time of 1:57.782, but the Ducati man's best was only 0.129s back.

Behind them Shinya Nakano made the most of his new Gresini-run factory Honda RCV to go third fastest, deposing teammate Alex de Angelis from the position in the final moments of the hour.

Bridgestone looked to have the early initiative once again at Brno, its riders filling the top eight positions.

John Hopkins was an impressive fifth fastest on his return from injury, riding the updated Kawasaki, while Chris Vermuelen was an encouraging sixth for Suzuki.

Toni Elias's Alice Ducati split the blue bikes with a surprising lap that put him seventh ahead of Loris Capirossi.

Tech 3 Yamaha's Colin Edwards was the top Michelin man in ninth while Marco Melandri completed the top ten on the second factory Ducati.

Dani Pedrosa, still nursing his wrist injury after a fall in practice for the German Grand Prix was the last of the 17 riders on the sole Repsol Honda.

Pos  Rider             Bike           Time
 1.  Valentino Rossi   Yamaha    (B)  1:57.782
 2.  Casey Stoner      Ducati    (B)  1:57.911  + 0.129
 3.  Shinya Nakano     Honda     (B)  1:59.021  + 1.239
 4.  Alex de Angelis   Honda     (B)  1:59.134  + 1.352
 5.  John Hopkins      Kawasaki  (B)  1:59.220  + 1.438
 6.  Chris Vermeulen   Suzuki    (B)  1:59.400  + 1.618
 7.  Toni Elias        Ducati    (B)  1:59.756  + 1.974
 8.  Loris Capirossi   Suzuki    (B)  1:59.770  + 1.988
 9.  Colin Edwards     Yamaha    (M)  1:59.965  + 2.183
10.  Marco Melandri    Ducati    (B)  2:00.082  + 2.300
11.  Sylvain Guintoli  Ducati    (B)  2:00.083  + 2.301
12.  Andrea Dovizioso  Honda     (M)  2:00.429  + 2.647
13.  Jorge Lorenzo     Yamaha    (M)  2:00.447  + 2.665
14.  Randy de Puniet   Honda     (M)  2:00.496  + 2.714
15.  James Toseland    Yamaha    (M)  2:01.074  + 3.292
16.  Anthony West      Kawasaki  (B)  2:01.128  + 3.346
17.  Dani Pedrosa      Honda     (M)  2:01.231  + 3.449