By Peter McLaren

Valentino Rossi may have finished the first test of 2008 in sixth position and over one second from the top, but the Italian was encouraged by the performance of his new Bridgestone-shod, pneumatic-valve, M1.

The Fiat Yamaha rider was sixth on the opening day at Sepang in Malaysia (+1.1secs), third on day two (+0.298secs), then sixth again on day three (+1.1secs) after finding only 0.4secs with qualifying tyres - compared with 1.3secs for Michelin-backed team-mate Jorge Lorenzo.

Indeed, Rossi believes that adapting to Bridgestone's one-lap rubber is currently his biggest challenge - so he was unsurprised to be outpaced over one lap by rookie Lorenzo, the reigning 250cc world champion.

"We've still got a lot of work to do, with the race tyres but especially with the qualifying tyres," said Rossi after the final day of testing. "This afternoon I tried out different rear qualifying tyres and wasn't particularly quick. In my opinion that's the area we need to work on the most with Bridgestone.

"It didn't surprise me that Lorenzo was faster because he went well at Jerez [in November]," added the #46. "He's gone well again here - during the race simulation he was close to my times, and then at the end when we were out on qualifying tyres he was even quicker than I was, but we were expecting that. I like him, and as two riders within a team we're perhaps the strongest out there."

Using race tyres, Rossi set a best of 2mins 1.852secs - faster than Lorenzo by 0.252secs - but still 0.8secs slower than reigning world champion Casey Stoner, 0.67secs behind Yamaha Tech 3's Colin Edwards, 0.136secs from Repsol Honda's Nicky Hayden and a fraction off the race pace of Rizla Suzuki riders Chris Vermeulen and Loris Capirossi.

"I think [Stoner's] still the man to beat, because with race tyres he has been quicker than us, so we have work to do," said Valentino. "He was also faster with the Bridgestone qualifying tyres so, like he demonstrated last year, he's very fast in qualifying configuration as well."

Whilst the tyre switch alone clearly hasn't removed Stoner's performance advantage, Rossi claims to be encouraged by his new rubber - and credits its predictability, balance and endurance above outright grip.

"In my opinion, the most important thing with Bridgestone is that the situation with the tyres is very clear," said the ex-Michelin rider, who suffered high-profile chatter problems in 2006 and then performance/endurance issues in 2007. "As we have a bike that has shown itself in the past to be a bit stubborn to set-up, having tyres whose behaviour and performance we understand and which 'jolt' less is very important for us.