Valentino Rossi has branded the online trolls who criticised fellow-Italian Andrea Iannone after his Australian Grand Prix performance "stupid" while stating "they are not my real fans."

Iannone was the target of vicious online abuse when he demoted championship leader Rossi to fourth at the climax of a breathless race at Phillip Island, a result that could yet have serious implications for the 36-year old's title aspirations.

Rather than losing four points to chief rival Jorge Lorenzo, Rossi saw his championship lead whittled away by seven. Still, the championship leader used the pre-event press conference in Sepang to hit out at those who had criticised Iannone.

"In reality they are not my real supporter," said Rossi, who now leads Jorge Lorenzo in the championship by a reduced eleven points. "Fortunately here it is difficult to follow because you are not in Italy," he explained. "I hear just after the race. It's a great shame because these people are stupid. This is the time of the social network where everybody can say his idea even if it's a very stupid idea.

"The people like to speak bad about other guys that are more lucky than them. That have more talent and are happier because they do what they want in their life. So a lot of time in my social network everybody has these guys who speak bad about your life, your mother."

As was the case in Phillip Island, when Rossi praised Iannone for his spirited performance while admitting it was a "great shame" he had missed the podium, he insisted his countryman did the right thing by running his own race.

"It's always a great shame because unfortunately you cannot speak with them. If you speak you only lose time. I'm very sorry for Andrea. He just did his race and it's normal that he tried to beat me."

Iannone was quick to dismiss questions that his approach would change as a consequence of the reaction of "a minority" and instead stated he was fully focussed on Sunday's race.

"In my Facebook and my Instagram I have a lot of comments. The 90 percent is positive and I think it's only the opinion. It's a minority compared to the other people. I am happy because I have a lot of support from the fans. I am looking forward and I'm focussed on this last races."