With both Repsol Honda riders sidelined, rookie Marco Simoncelli finished as the top RCV rider with sixth place in Sunday's Australian MotoGP round.

Fast all weekend, the San Carlo Honda Gresini rider used his MotoGP-best of fourth on the grid to launch an early podium challenge, before fighting fellow rookie Ben Spies for fifth for much of the race.

Spies overtook Simoncelli for the final time with five laps to go and they finished just under three-seconds apart. Sixth equals Simoncelli's best result of the year.

"It was a really nice race and I enjoyed it a lot, so I am happy," said the former 250cc world champion. "I got a good start and moved into third place on the first lap and then stayed in the group with Rossi, Hayden and Spies.

"We had a great battle and it was really good fun. When Hayden passed me and went after Valentino I was left with Spies for the rest of the race but I managed to keep my pace up and make an attempt to pass him at the end, although unfortunately he was a little too fast for me. Anyway, as I said I am delighted with a really nice race."

"Simoncelli was able to stick with the best riders in the category and the only reason he couldn't hold off Spies was because his tyre was spent," explained team manager Fausto Gresini. "We are happy with his performance because once again we have seen the progress he has made over these three flyaway races. Marco is constantly improving and that is very important to us."

But, once again, things weren't so positive on the Marco Melandri side of the pits. The 2011 WSBK rider lost eighth to Aleix Espargaro on the very last lap.

"This race was just the same as all the others this season, I struggled throughout and at the end I was passed by Espargaro," said the Italian. "He passed me between the penultimate and final corners and he looked like he was out for a stroll, whereas I was fighting with the bike and couldn't hold him off.

"I got a good start but over the first few laps my tyres felt like they were made of ice and by the time they had heated up I couldn't make any progress."

"We are still working hard with Melandri but he is not happy," said Gresini. "He is not getting on with this bike but this is the bike we have and we have to be professional and do our best to get results in the final two races. This situation makes me very unhappy."