Returning seven time MotoGP champion Valentino Rossi paid tribute to the work done by Jorge Lorenzo and Yamaha during his two seasons away from the M1.

At the end of his first dry day on a 1000cc Yamaha, during testing at Sepang, asked Rossi to compare the present M1 with the bike he had left in 2010.

"For me it is better," replied Rossi. "I think Yamaha, with Lorenzo and his team, have done a very good job without me, because the bike is better clearly."

In what way is it better?

"The electronics system is more easy and especially to work on the system. It is very clear what we have to do on the bike," Rossi explained.

"Also the front feeling has improved more than 2010 - and of course there is more power from the engine because it is now 1000cc."

Rossi, back with Yamaha after two unsuccessful seasons at Ducati, was fourth fastest and 0.427s from the top during day one of testing - a result he described as a 'big relief'.

Reigning double champion Lorenzo was second quickest, just 0.008s from Honda's Dani Pedrosa.