Runaway MotoGP World Championship leader Jorge Lorenzo finished Friday practice for the Czech Republic Grand Prix with a half-second advantage Dani Pedrosa, his nearest title rival.
Lorenzo and Pedrosa exchanged the top spot throughout the hour session, with Lorenzo re-taking then extending his advantage with 17 minutes to go - just as light rain began to fall.
That effectively ended the session, and riders only returned to do a practice start.
World champion Valentino Rossi, riding in his third event back from a broken leg, briefly ended the Lorenzo/Pedrosa domination at the midway point of the hour on his way to third place, 0.606sec behind Fiat Yamaha team-mate Lorenzo.
Pedrosa's Repsol Honda team-mate Andrea Dovizioso was the final rider within one-second of Lorenzo, with fifth placed Nicky Hayden 1.071sec from the top for Ducati.
Fellow American Colin Edwards made a promising start to be the leadings satellite rider in sixth for Monster Yamaha Tech 3, with Hayden's team-mate Casey Stoner only seventh fastest.
San Carlo Honda Gresini's Marco Simoncelli recovered from an early fall to finish the session in eighth place, as the top rookie, with fellow newcomers Ben Spies ninth for Tech 3 and Alvaro Bautista tenth for Rizla Suzuki.
Loris Capirossi was a fraction slower than team-mate Bautista is eleventh, two seconds from Lorenzo, with Aleix Espargaro the top satellite Ducati in twelfth for Pramac.
Marco Melandri made a slow start to the weekend with 14th place, while Randy de Puniet - who broke his leg at the Sachsenring on July 18 - took 16th for LCR Honda (+2.969sec).
Alex de Angelis, who continues to replace Hiroshi Aoyama at Interwetten Honda, was 17th and last (+3.883sec).
16. de Puniet
17. de Angelis