Suppo confused by Ducati's problems

The champions have struggled for pace in both of the last two races, and although neither Jerez nor Estoril were among Ducati's strongest tracks in 2007, they still fared far better last year than they have this season.

"It's strange, because the conditions here are similar to last year, yet we are struggling," Suppo told Italia1 television. "We need to try to understand why. The set-up of the bike is very similar to last year's."

Suppo said he had no concerns world champion Casey Stoner's contribution - with the Australian significantly faster than teammate Marco Melandri, and quickest of all in wet practice on Friday.

"This past winter Casey did some excellent testing and won the first race," said Suppo. "Yesterday morning in the wet Casey was seventh tenths quicker than everyone else, so there's no doubt Casey is always Casey.

"There's something we are really struggling to identify in the grip that has changed a lot. We must work a lot on it."

Although Michelin has regained ground on Bridgestone in the tyre war this season, Suppo does not think Ducati's problems are down to Bridgestone.

"Obviously we discuss tyres together, so there's nothing different than expected," he said.

"It's simply that we can't understand why, in similar conditions to last year - and we had raced here just six months ago, not one year - we can't repeat the lap times we were setting then. We will calmly find out."