World Championship leader Casey Stoner moved to the top of the Aragon MotoGP timesheets during an extended Saturday morning practice session.
FP3 was lengthened from 45 to 75-minutes after the cancellation of Friday's afternoon session, due to power shortages at the circuit.
Stoner had been third fastest, half a second from the top, in Friday's lone session, but led much of the Saturday morning track time. The Repsol Honda star's best time was one-second under the fastest on Friday (by Dani Pedrosa) and was set on his 8th lap of 24.
Pedrosa closed to within 0.062sec of Stoner at the very end of the session, but the belief is that Pedrosa used a new tyre while Stoner was setting a similar pace on used rubber.
A near 0.7sec then separated Pedrosa from a surprise third fastest Randy de Puniet.
The Pramac Ducati rider, who had been the top Desmosedici in sixth on Friday, made the most of several laps in Andrea Dovizioso's slipstream to move as high as second in the closing stages, before Pedrosa moved back ahead of him.
Dovizioso finished the session just over 0.1sec behind the Frenchman in fourth for Repsol Honda, with Gresini Honda's Marco Simoncelli fifth and the final rider within one-second of Stoner.
Ben Spies suffered a turn two fall on his way to sixth for Yamaha (+1.104sec) marking a clear improvement on his eleventh place in Friday. But team-mate and reigning world champion Jorge Lorenzo moved in the other direction, slipping from second on Friday to eighth this morning.
Lorenzo starts this weekend 35 points behind Stoner in the championship.
Separating the two factory M1s was Suzuki's Alvaro Bautista, who improved from 13th on Friday to seventh (+1.150sec) this morning.
Valentino Rossi has an aluminium (rather than carbon fibre) front chassis to try on his factory Ducati this weekend. The Italian lowered the gap to the top slightly this morning, from 1.4sec to 1.2sec, but finished the session one place lower than yesterday, in ninth.
Team-mate Nicky Hayden, riding the previous GP11.1, was a fraction slower than Rossi for tenth place. Aspar's Hector Barbera was eleventh with rookie Cal Crutchlow the top Monster Yamaha Tech 3 rider in twelfth.
The one hour qualifying session will take place as usual this afternoon.
3. de Puniet