Marco Simoncelli, who saw his hopes of a first MotoGP victory - and rostrum – disappear when he crashed out of the lead of the wet Spanish Grand Prix, was straight back on top of the timesheets during opening practice at Estoril in Portugal.
The San Carlo Honda Gresini rider was competitive throughout the dry 45-minute session and moved ahead of Repsol Honda's Casey Stoner by 0.209sec on his 20th and final lap.
Qatar winner Casey Stoner, looking to make up for lost points after Jerez, finished a fraction in front of team-mate Dani Pedrosa.
Pedrosa was riding his first MotoGP laps since his recent collarbone operation, aimed at curing the arm numbness he has struggled with ever since last October's Motegi crash.
World champion and 2011 world championship leader Jorge Lorenzo, winner from pole at all three of his previous Estoril MotoGP appearances, appeared in the astronaut livery of previous years.
The Factory Yamaha rider lapped 0.381sec slower than Simoncelli to be the top non-RCV rider.
Valentino Rossi, whose Jerez crash brought down Stoner, was fifth quickest for Ducati and 0.537sec from Simoncelli. Another Italian, Andrea Dovizioso, was sixth for Repsol Honda.
Monster Yamaha Tech 3's Colin Edwards was the top satellite bike rider in seventh, with Lorenzo's team-mate Ben Spies - looking to make his first Estoril MotoGP start after crashing on the way to the grid last year - eighth after running ran through the gravel in the opening minutes.
Ducati riders Hector Barbera (Aspar) and Randy de Puniet (Pramac) completed the top ten. Factory Desmosedici rider Nicky Hayden was 14th, one place in front of rookie Cal Crutchlow, after losing time when his bike stopped out on track.
Rizla Suzuki's Alvaro Bautista, returning to action after breaking his left femur during practice for round one in Qatar on March 18, was 17th and last. The Spaniard ride for 20 laps, the best of which was three seconds behind Simoncelli.
Bautista has confirmed that he will continue riding for the rest of the weekend, rather than hand over to test rider Nobuatsu Aoki.
Second free practice takes place this afternoon.
Friday practice (1):
10. de Puniet