Nine-time world champion Valentino Rossi is adamant that Yamaha must do better in the 2021 MotoGP season and won't be using frozen engine development as an excuse.

The Italian believes that lots can be done to improve the M1's performance without having to get inside the motor.

"The engine is frozen but it's not an excuse. I mean, in MotoGP now you can make a lot of things around the engine to improve the performance," said Rossi.

"From the electronic side, from the way to keep the engine with a lower temperature, and the pipes.

"So even if you cannot go inside the engine, you have a lot of different issues that you can improve. So for me if Yamaha work well and in the right direction we can do better."

"I have to work a lot on myself. We have to improve some areas like qualifying, which is so important now.

"Also we will push as always on Yamaha to try to make a good job during the winter to try to improve some areas. Because in the last years and also this year we were strong at the beginning of the season, but we struggled compared to our competitors in the second half because they are able to fix all the new things.

"With Yamaha, the end of the season is not easy. So next year will be a hard challenge and we need to arrive ready from the first race."