The GP8 has much to live up to, with the Bridgestone-shod GP7 having won a total of 11 out of the 18 races last season - and all three premier-class world titles - but the new machine didn't disappoint...

March's Spanish Grand Prix at Jerez had been the scene of Stoner's second-worst finish with the GP7, a fifth position, but the 22-year-old was on much more effective form with the GP8.

Stoner posted a best time of 1min 40.221secs, a huge 1.2secs inside his best race lap from the grand prix and enough to keep the young Australian 0.134secs clear of closest rival Dani Pedrosa - despite a fast afternoon fall.

"This first day with the GP8 was really positive for us," said Stoner. "I immediately felt at home on the bike because it's pretty similar to what we rode last season. Today we were quite a bit faster than we were when we raced here back in March, which is very important because we have improved at a track that used to be a bit difficult for us. We found a very good set-up which could also be good at other circuits. We used 2007 spec tyres today, tomorrow we will start with Bridgestone's new tyres. The only bad moment of the day was the crash, but these things can happen. I'm okay though, so everything is fine."

Meanwhile, new team-mate Marco Melandri continues to make a steady to his Ducati career and set the 12th fastest day one lap time, 1.668secs behind Stoner.

"We started working on chassis geometry to adapt the bike to my riding style," said the former Honda Gresini rider. "Today we made some good choices on settings and also some not so good choices, but every change teaches us something more about the bike which is very important. Towards the end of the day we found a set-up that I liked better, even though I don't yet feel totally at ease. We have work to do and I'm not at all worried about that."

The Jerez test will conclude on Thursday and is the last chance for track time before the MotoGP winter ban starts on December 1. Testing will then resume on January 22 at Sepang.