Reigning seven time MotoGP world champion Valentino Rossi has been denied a perfect sweep of 2010 pre-season testing after losing out to Casey Stoner on the very final night of the Qatar test.

The Italian had been fastest on all five previous 'days' - four at Sepang in Malaysia and then Thursday night in Qatar - but Stoner, runner-up to Rossi on each of those occasions, finally broke the Fiat Yamaha rider's dominance on Friday night at Losail.

The Ducati star, winner at Qatar for the past three seasons, had been 0.315sec behind Rossi on the opening night, but reversed the situation by dipping 0.049sec under Rossi's Thursday time - despite a fall at turn two.

Meanwhile, Rossi was left 0.507sec behind the Australian on Friday, but still in second, after failing to improve.

Indeed, Rossi's team-mate Jorge Lorenzo (joint sixth) was the only M1 rider to lap quicker on the second night, with Tech 3 riders Colin Edwards (eighth) and Ben Spies (tenth) - both of whom also fell at turn two on Friday - also slower than on Thursday.

The 14 other riders all went faster, notably Andrea Dovizioso, who salvaged pride for Honda with a much better final night, the Italian moving from sixth to third (0.526sec from Stoner) after a substantial 0.932sec improvement.

However LCR's Randy de Puniet, fastest on day one, was the only other RCV rider in the top ten - the Frenchman being tied for sixth with Lorenzo - and Dovizioso's factory team-mate Dani Pedrosa was left in a lowly 13th, over 1.5sec from Stoner.

"I'm still struggling with the bike moving quite a lot at the front and that's caused by issues at rear," said the Spaniard.

Just as at the previous Sepang test, Stoner's team-mate Nicky Hayden jumped up the order during the last session. The American knocked 0.74sec from his Thursday best for fourth on Friday behind Dovizioso and fifth overall behind Spies. Hayden was yet another rider to crash at turn two.

Also starting the season in a positive frame of mind will be Rizla Suzuki's Loris Capirossi, who leapt up the order from eleventh to fifth (sixth overall) with a solid 0.904sec Friday night improvement as he tried new chassis and swingarm components.

Pramac's Mika Kallio was ninth on Friday and tenth overall, just ahead of team-mate Aleix Espargaro, while Suzuki rookie Alvaro Bautista progressed from 17th and last on Thursday to twelfth on Friday.

The last four places at the test, behind Pedrosa, were occupied by Marco Melandri (Gresini Honda), Hector Barbera (Aspar Ducati), Hiroshi Aoyama (Interwetten Honda) and Marco Simoncelli (Gresini Honda).

Nevertheless, Simoncelli was only two seconds slower than Stoner - and 0.6sec from tenth placed Kallio!

The first race of the 2010 MotoGP season takes place at Qatar from April 9-11.