Fresh from a second dry-weather podium on the Ducati at Misano, Valentino Rossi believes this weekend's Aragon MotoGP round will test whether a leap forward has been made with the Desmosedici GP12.

Rossi secured second place at Misano last time out with raft of changes to the bike and then tested again after and has brought a new swingarm to the Spanish track which he says gives added corner-exit grip but is kinder on tyres.

"It's a big test for understand our level because Misano was a good weekend, a great race and a great result for us. Now we have to understand here and in the next four races if, in reality, we have been a step forward," said Rossi, speaking at Aragon," said The Doctor, speaking at Aragon.

"This track is good, I like a lot, but is so difficult to go fast. Especially for me as it's not the best result in the last two years so is important for improve my line and my style in this track and understand if we are closer to the top guys."