Stoner struggling with wet set-up

The former champion was second in the morning, despite a crash, but was 0.7 seconds slower than pace-setter Nicky Hayden.

"So far things haven't gone too well and we're still a long way off with the set-up," said Stoner.

"For the past few races we've struggled a little more than usual in the wet and even though we've managed to sort it out in the past we've not done so here yet. We're lacking a bit of rear traction and we need to improve corner entry too."

He suspected that standing water had contributed to his accident in practice one, and added that it had not caused any further problems for his already-injured wrist.

"This morning I crashed without any kind of warning from the bike although there was a lot of water at that particular point and maybe I was a little outside the usual line," said Stoner.

"I wasn't hurt and in general the wrist isn't as bad in the wet anyway."

But despite his frustration about today's performance, Stoner believes Ducati can resolve their issues in time for qualifying tomorrow even if the rain continues.

"We know what changes we need to make to the bike tomorrow if the conditions are the same," he said. "We know we can do better than that, we just need to work hard."