Jorge Lorenzo has not lost hope of matching the Hondas in the inaugural Austin MotoGP race this weekend, despite his Yamaha being 1.6 seconds off the pace in practice.
Honda had dominated the pre-season test at Austin and Marc Marquez was a class apart on the opening day of practice on Friday.
As track conditions improved for the second session, Honda cemented its superiority by filling the top three with Marquez, his works team-mate Dani Pedrosa, and LCR rider Stefan Bradl.
Even the latter was half a second quicker than Lorenzo.
The world champion admitted Yamaha was struggling, but remained optimistic.
"As in the test, we still have a lack of grip in the middle of the corners," Lorenzo told the official MotoGP website.
"In the morning I was surprised to be quite close to Marc, but in the afternoon when the track improved, they improved much more than us.
"From the outside it seems that the Honda can turn much better. When they open the throttle, they can pick the bike up in a shorter time. We stay on the angle for a long time, with no grip on the rear. It's difficult to ride like that.
"But I'm positive. I think anything is possible. Tomorrow, we can improve the bike a lot and get much closer."
Valentino Rossi was one place behind Lorenzo on the second Yamaha.
"The practices are not so bad because we improved a lot compared to this morning and we could stay close to Jorge," he said.
"Unfortunately the Hondas are very fast, which we already knew from the test.
"We hope to make it better this weekend but especially Marquez is very fast and also Pedrosa and Bradl are faster than us so we have to work and try to improve for tomorrow."