The 2006 season - when technical problems, accidents, injuries and Nicky Hayden combined to end Valentino Rossi's five-year reign - was seen as something of a freak occurrence which, paddock wisdom assured, would be quickly corrected during 2007.

So, when Rossi lined up on pole position for the season opening Qatar Grand Prix, race - and probably title victory - looked a formality… But by the end of the first lap Ducati's new signing, Casey Stoner, riding in only his 17th MotoGP race, had blasted past Rossi on his powerful Desmosedici GP8 - then shocked the MotoGP world by shrugging off the Italian to take a debut win by 2.8secs.

Rossi restored order with victory next time out in Jerez, when Stoner was just fifth, but the Australian then won the next two rounds and the full extent of Stoner's title threat was confirmed next time out at the French Grand Prix.

The #27 may not have won in the rain at Le Mans but, in conditions close to a worse case scenario - a wet, twisty track that prevented his Ducati from exploiting its horsepower advantage - Stoner still claimed third position, behind only wet weather experts Chris Vermeulen and Marco Melandri, and crucially again beat Rossi.

The French GP was also the home race of Rossi's tyre supplier Michelin and the second all-Bridgestone podium of the season signalled the dramatic shift in power between the two leading MotoGP brands.

New rules for 2007 forced all the Michelin and Bridgestone riders to select their tyres before the grand prix weekend had begun. Bridgestone, which won four races in 2006, adapted almost seamlessly to the change, helping its leading riders to run consistently up front - but the Michelin rubber was more hit and miss, much to the frustration of its riders. More of that later…

Meanwhile, Rossi called up Mugello magic to claim a record sixth home victory in the Italian Grand Prix - reducing the deficit to Stoner to just nine points - before Stoner retaliated with a thrilling victory over Rossi at Catalunya, then a dominant win at a damp Donington Park.

The following Dutch TT at Assen looked to be a turning point for Rossi after the former five times MotoGP world champion finally beat Stoner in a straight head-to-head for the first time this season - but the Italian was immediately robbed of any title momentum when he crashed out of the following German GP.

When Stoner then dominated the US Grand Prix, just before the summer break, and the Czech Republic Grand Prix, just after it, Rossi's title challenge was left firmly on the ropes - and even worse was to follow.