250cc World Championship leader Hiroshi Aoyama got his Malaysian Grand Prix weekend off to a perfect start by setting the fastest lap time in Friday practice at Sepang, while title rival Marco Simoncelli managed just tenth.
Reigning champion Simoncelli has won four of the last five races to close to within 12 points of the Scot Honda rider with two rounds to go, but momentum swung back in Aoyama's favour on Friday as Simoncelli's Metis Gilera lapped 1.2sec slower than the Japanese.
Thai rider Ratthapark Wilairot made it two Honda riders in the top three as he began the nearest thing to a home grand prix with a last-gasp third, just 0.052sec behind Aoyama.
Mike di Meglio had led the session with six minutes to go being pushed down to fourth, with Aspar Aprilia team-mate and third in the championship Alvaro Bautista one place behind.
Double 2009 race winner Hector Barbera sat smiling and shrugging his shoulders in casual clothes at the start of the session in an apparent pay protest.
The 2010 MotoGP rider soon took to the track for Pepe World Aprilia and was fastest of all with 20 minutes to go, before claiming sixth at the flag
Friday practice - Sepang:
1. H. Aoyama (Honda)
2. Debon (Aprilia) +0.013sec
3. Wilairot (Honda) +0.052sec
4. di Meglio (Aprilia) +0.098sec
5. Bautista (Aprilia) +0.284sec
6. Barbera (Aprilia) +0.410sec
7. Pasini (Aprilia) +0.888sec
8. Pesek (Aprilia) +0.977sec
9. de Rosa (Honda) +1.245sec
10. Simoncelli (Gilera) +1.262sec