Reigning world champion Valentino Rossi completed a clean sweep of both MotoGP pre-season tests at Sepang in Malaysia, courtesy of a record-breaking Friday lap time.

Undefeated at the first test of the year on February 4-5, the Italian picked up where he left off during this week's return visit. The Fiat Yamaha rider was fastest on both Thursday and Friday, clocking a flying 2min 0.271sec on lap 12 of the last day.

That was 0.654sec under his fastest lap from the first test and beat the official lap record for a MotoGP bike at Sepang, which Rossi himself recorded during qualifying for last October's grand prix, by 0.247sec.

"I'm really happy to have beaten my pole record, it's a good feeling to be this fast in testing," said Rossi. "I did this with an old tyre but we also got the chance to try a very good new tyre from Bridgestone today, which I hope we will use from the first race.

"Our bike is in great shape; we need to do a bit more work on the electronics but in general everything is better, especially the rear grip and the engine. Yamaha have been very clever to develop this new bike whilst keeping the best parts of the old one, I'm very happy about it."

Rossi also found time to do a few laps on the Yamaha test team bike: "It was good to get the chance to try the Japanese test bike, hopefully the feedback I gave them will help us in the future."

After a perfect start to the new year, The Doctor is now expecting a more challenging time during the final pre-season outing, at Qatar on March 18-19.

"We have been on top for all four days here, but now we are looking for the next test in Qatar because usually that track is more difficult for us. For the bike and also for me. I don't like the track as much as Sepang," he said.

"The Qatar test will be very interesting to understand the level between me and Casey," Rossi added. "I think me and Casey are faster than the others now and unfortunately Jorge [Lorenzo] was not here."

Stoner, second to Rossi on all four days at Sepang, also upped his pace significantly on the final day - Ducati's 2007 world champion setting a best lap time just 0.241sec behind the Italian.

Rossi noted that the surprise of the day was the performance of Stoner's factory Ducati team-mate Nicky Hayden, who improved on his day one lap time by over 1.5sec to leap from eleventh to third - just 0.432sec from Rossi.

"We had a few good surprises today. Nicky is fast. I think that is the greatest surprise and it means that the new [big bang] engine from Ducati is more easy for everybody," said Rossi.

Rossi was also impressed with the pace of Monster Yamaha Tech 3 riders Colin Edwards and rookie Ben Spies. The Texans were an evenly-matched fourth and fifth, three-quarters of a second behind Rossi and the last riders within one second of the top.

"Colin is going good, so the old school still rules!" smiled Rossi. "And also Spies did a good test. But I don't know what happened to Dani..."

Pedrosa, usually Honda's top rider, was only seventh and eighth respectively over the two days of testing.

Finishing between Spies and Pedrosa on the final day were Suzuki's Loris Capirossi (sixth) and Pedrosa's Repsol team-mate Andrea Dovizioso (seventh).

After some tough days with the new 2010 Honda, reigning 250cc world champion Hiroshi Aoyama claimed a confidence boosting ninth for the new Interwetten outfit - 1.168sec from Rossi and the top satellite RCV.

Fellow rookie Alvaro Bautista also made a clear stride forward with tenth for Rizla Suzuki.

Having claimed to have made something of a breakthrough at the end of Thursday, LCR Honda's Randy de Puniet backed his words up by finding over half a second on Friday to move from 15th to eleventh.

San Carlo Honda Gresini team-mates Marco Melandri and Marco Simoncelli were the only riders to fall on Friday.

Melandri's was a minor spill, but Simoncelli was taken to hospital for precautionary checks after a huge highside at turn seven. The Italian was later released but played no further part in the test.

Melandri left Sepang with the twelfth fastest lap time, ahead of Hector Barbera (Aspar Ducati), Mika Kallio (Pramac Ducati), Aleix Espargaro (Pramac Ducati) and the sidelined Simoncelli.

Lorenzo missed the whole test due to a hand injury in a motocross accident. The 2009 title runner-up plans to return for the Qatar test.

The first race of the new season will also be held at Qatar, on April 11.