Valentino Rossi began the Grand Prix of Catalunya weekend fastest in Friday free practice, during a session that saw a fall for MotoGP World Championship leader Casey Stoner, a surprise premier-class debut for Gabor Talmacsi and Nicky Hayden's best session as a Ducati rider.
Reigning six time MotoGP world champion Rossi, pushed back to third in the points behind Stoner and Jorge Lorenzo, chased team-mate Lorenzo for much of the session before slicing ahead in the closing stages.
The Fiat Yamaha star finished the hour 0.302sec quicker than home star Lorenzo with Stoner 0.598sec from the #46 for Ducati. Stoner suffered a lowside fall from his Desmosedici with 15 minutes of the hour remaining and had to finish the session on his spare bike.
Fourth in practice, and where he has finished the last two races, was Repsol Honda's Andrea Dovizioso, with the satellite LCR Honda of Randy de Puniet just behind him after an impressive performance.
But perhaps the happiest rider in the top six was Hayden, who enjoyed by far his best session of the year so far by lapping half a second slower than team-mate Stoner.
Hayden is yet to finish a race higher than twelfth on the Desmosedici, something he will be aiming to change at round six - although it should be noted that the American was still 1.1sec slower than Rossi.
Loris Capirossi was the leading Rizla Suzuki rider in seventh with Colin Edwards eighth for Monster Yamaha Tech 3.
A surprise ninth place went to Scot Honda's Yuki Takahashi, whose place on the MotoGP grid has been put in doubt by Talmacsi's sudden arrival alongside him.
The Japanese rookie responded excellently by lapping in the top half of the field, while former 125cc world champion Talmacsi closed the gap to the top from six seconds at the halfway mark of the hour to 4.6sec by the finish as he unsurprisingly rounded out the 19 rider field.
The final place in the top ten went to Tech 3's James Toseland, with Marco Melandri eleventh for Hayate and Sete Gibernau twelfth on his comeback from collarbone surgery.
Chris Vermeulen was 13th on the second Suzuki, with Dani Pedrosa, who cracked his thigh bone in a near highside last time out at Mugello, 14th at the end of day one. Pedrosa, who won last year's race, was due to try a modified chassis for his Repsol Honda during the session.
This weekend's event is the first this year to feature dual compound rear slicks - harder on the right than the left - and also the first time that the extra-hard rear compound has been on offer.
5. de Puniet
16. de Angelis