"Marquez is very spectacular. The bike moves, slides and he always touches his elbow on the track. He is very good and already so fast.
"It is particular, a strange riding style. Something new. Me and Jorge, our riding style is more 'classic'. Marquez is something different.
"Okay the Honda is different. But this thing where he touches his elbow in every corner is very good - especially for the people that watch the races."
Marquez and Rossi finished the final day of Sepang testing in second and fourth respectively.
Rossi has long praised the potential of Marquez, even before the newly 20-year-old had turned a wheel in MotoGP.
"I expect - and said three or four months ago - that Marquez can fight for victory from the start of the season," Rossi commented at the first Sepang test.