Yamaha says Jorge Lorenzo's stand-in Katsuyuki Nakasuga is pushing himself too hard

Test rider and All Japan Road Racing competitor Nakasuga fell at the final corner in the morning and Turn 13 in the afternoon.

"I wanted to learn as much as I could during the sessions," said Nakasuga, who was slowest bar the injured Hector Barbera in the morning and last of all in the afternoon.

"Unfortunately I crashed this morning but thought that afterwards I would be able to relax a little once it was out of the way. Unfortunately again I crashed this afternoon and I'm not sure why.

"I'm feeling disappointed about it but will come back tomorrow and try to make sure we improve and have a day without crashing."

Team manager Wilco Zeelenberg reckons Nakasuga was simply trying too hard and needs to relax tomorrow to boost his confidence for the rest of the weekend.

"It wasn't the plan to crash in both practices but you can imagine how difficult it is to take on this challenge," said Zeelenberg.

"Nakasuga-san put a lot of pressure on himself and maybe tried a little too hard too early.

"We need to help him find a rhythm and of course he is lacking a bit of speed compared to his competitors. We need to step up a bit tomorrow, not an easy task with the high level of competition on the track."

Yamaha team director Massimo Meregalli agreed that Nakasuga was feeling the pressure too much, but is confident he has the pace to impress.

"Nakasuga-san had a difficult start; maybe he felt too much pressure for his first day in MotoGP," said Meregalli.

"At the beginning of the season in testing he put together some great laps so I think he can improve tomorrow."