Jorge Lorenzo says Yamaha's one-two in final MotoGP practice in Qatar is evidence of major progress by the manufacturer over the winter.
Works team rider Lorenzo was backed up by Tech 3 Yamaha's Cal Crutchlow in second, with the Briton's team-mate Andrea Dovizioso fourth.
"I am very happy with today because we improved a lot on yesterday's lap time," said Lorenzo. "I'm also happy for Cal in second, the bike seems much better than last year for us.
"I think we have even more potential for improvement tomorrow. We still have a few issues to solve, especially corner entry, but we manage to keep a good pace. I'm going to try my hardest for qualifying tomorrow and see what we can do."
While three of the Yamahas were in the top four, the fourth was only 11th – as second factory rider Ben Spies crashed his primary bike then encountered electrical issues on his spare.
"It was a rough session tonight," said Spies. "We've had a good weekend up to now, unfortunately tonight was the most important session for us.
"I went out to do a race simulation and I think I didn't let the front tire heat up properly. I need to check the data to confirm it but I put the blame firmly on myself for it. Unfortunately the second bike just didn't run right so a wasted session for us."