Brno - Spaniard Dani Pedrosa took the honours in Friday's free practice for Sunday's Czech Republic MotoGP.
The Honda rider, aiming to follow up last weekend's win in Indianopolis, posted the quickest time of 1min 56.858 seconds.
In second came his compatriot Jorge Lorenzo, who leads Pedrosa by 18 points in the championship standings.
the 2010 world champion and winner on the Brno circuit 12 months ago,
fell from his Yamaha in the second session without coming to any harm.
time was 0.053s behind Pedrosa, with Italian Andrea Dovizioso in third
at 0.197 in his last season with Yamaha after signing a two-year deal
A notable absentee from this weekend's action in the
Czech Republic is defending world champion Casey Stoner, who has
returned to Australia to undergo surgery on his broken ankle.
Honda rider fractured his right ankle in qualifying for last weekend's
Indianapolis Grand Prix although he decided to race and finished fourth.
Stoner has conceded that the injury has left his title defence in his last season competing in tatters.
He is placed third in the overall standings on 186 points.
Results from Friday's free practice sessions ahead of the Czech Republic MotoGP on Sunday:
Dani Pedrosa (ESP/Honda) 1min 56.858sec, 2. Jorge Lorenzo (ESP/Yamaha)
at 0.053s, 3. Andrea Dovizioso (ITA/Yamaha) 0.197, 4. Cal Crutchlow
(GBR/Yamaha) 0.357, 5. Stefan Bradl (GER/Honda) 0.392, 6. Valentino
Rossi (ITA/Ducati) 0.457, 7. Ben Spies (USA/Yamaha) 0.588, 8. Alvaro
Bautista (ESP/Honda) 0.643, 9. Randy de Puniet (FRA/ART) 1.809