Aussie Casey Stoner comfortably set the fastest time in Valencia today after producing a brilliant series of fast laps in the final minutes of opening practice for Sundays final MotoGP race.
In cloudy but windy conditions, Stoner didnt move to the top of the timesheets until the final six minutes when he moved just 0.169s clear of Fiat Yamaha rival Jorge Lorenzo.
On his next lap he extended his advantage to 0.353s and just less than three minutes of the session remained when his best lap of 1.32.813 moved him 0.448s ahead of the Spaniard.
Lorenzo hit back with a lap of 1.33.195 late on to cut the gap to the 2007 world champion but it was first blood to factory Ducati rider Stoner with another impressive showing.
Successive victories in Australia and Malaysia have given him a slender chance of snatching second place from Lorenzo in the final championship standings.
Lorenzo though only needs to score one-point to clinch second behind Yamaha YZR-M1 team-mate Valentino Rossi.
Lorenzo dominated for long periods in the session and his best lap kept Repsol Honda rider Dani Pedrosa at bay by just 0.046s.
Nine-times world champion Rossi had to settle for fourth and he never led at any stage during a tough session for the 30-year-old.
He ran of the track at the first corner shortly after the halfway stage and eventually clocked a best time of 1.33.499 to finish a massive 0.686s adrift of Stoner.
Rossi is chasing his seventh victory this weekend and he was ahead of Randy de Puniet on the LCR Honda.
The majority of eyes in today's practice session were fixed firmly on the performance of Texan Ben Spies.
The reigning World Superbike champion made his Yamaha debut today and produced an encouraging start.
The triple American superbike champion logged a best time of 1.35.052 to finish in 15th position. He was faster than Chris Vermeulen on the factory Suzuki and his best time was only 0.187s behind British rider James Toseland, who Spies will replace in the Monster Yamaha Tech 3 squad in 2010.
Toseland ended up 13th quickest with a fastest time of 1.34.865, but was 0.7s adrift of team-mate Colin Edwards, who could still claim fifth in the championship from Andrea Dovizioso.