Ducati MotoGP rider Jorge Lorenzo says a planning error was to blame for his poor Argentinian Grand Prix practice showing on Friday.
Lorenzo was one of several stars to struggle on the opening day of running at Termas de Rio Hondo, ending up 18th in second practice and 1.122 seconds off the pace set by Yamaha's Maverick Vinales.
That means the three-time champion faces the prospect of having to battle his way through Q1 on Saturday, if forecast rain prevents him from moving into the combined top 10 in third practice.
The Spaniard believes his position is not representative, as he wanted a medium front tyre for his final run, but was sent out on the soft and only realised at the end of the session.
"We made a mistake on planning with the tyres," he explained.
"[We used] the softer one when the conditions were not [good] for the soft. I didn't know, I thought I had the medium.
"I didn't understand why the front was closing so much, but then after practice I understood that we made a mistake.
"And this for sure meant we missed not the top five, but closer [to the top] than where we are now.
"We are 18th, but we are very close. With the right front tyre for sure we would be much better in the classification."
Lorenzo had a tough Ducati debut in Qatar last month, finishing only 11th, but feels "optimistic" of a better showing in Argentina.
"If it's dry, we can make a good race I think," he said.
"Let's see if we can make qualifying in the dry and we will be much further forward.
"I'm optimistic because I found some good feelings on some exits.
"Let's see if tomorrow we can make another step forward, and for sure much be more explosive with the right front tyre and pushing to make one fast lap."
DOVIZIOSO 'ANGRY' AFTER MYSTERY PROBLEM
Andrea Dovizioso led the way for Ducati in Qatar, fighting for the win with Vinales and finishing second, but he also finished the first day in Argentina down the order, in 14th and lamenting a mechanical problem.
"We don't know [what the problem was]," said Dovizioso.
"Electronics, clutch or something like that, we don't know. We're working now to try and understand exactly what happened.
"I don't think it's something big, but it's big to manage the bike because the grip is very low here.
"I couldn't slide how I wanted, so I couldn't decide the line and it was very bad.
"But the negative point is the position. I am angry about that because tomorrow can be wet and it's something that doesn't have to happen."