Andrea Dovizioso was at a loss to explain the difficulties he faced as practice for the Jerez MotoGP got under way in Spain on Friday.
Dovi's best lap time of 1m 40.884s left him in 12th position overall based on the combined times from FP1 and FP2, 0.018s ahead of Ducati test rider Michele Pirro and behind Pramac Racing's Andrea Iannone and Nicky Hayden
on the second factory GP13.
“It was really difficult this afternoon, and I'm not completely sure why,” he said.
“The grip was much worse for all the Ducati riders, and it was much harder for me to be precise and stay on my lines.
“We must understand if we can improve that sensation through the set-up, but this is the bike and I just have to adapt,” he added.
“I'm trying to stay calm and work in order to have a good session tomorrow morning.”
Development rider Pirro, meanwhile, who is fulfilling the first of his three wildcard rides for Ducati this season, was 13th fastest overall as he tests a series of new parts for the Desmosedici.
“It was a positive day in the sense that I'm back doing what I like most—competing,” Pirro said.
“There's work to be done because I'm still losing time in some sectors, but I'm satisfied overall because I haven't raced since November.
“Tomorrow we'll try to continue to dial in the GP13 because this is a new package in terms of frame, swingarm and engine.
“We're trying to improve everything, take another step, and get things ready for the race,” he added.
“I hope to pay Ducati back for the faith they've placed in me, and I really want to thank them for this opportunity.”