Danilo Petrucci was scathing over Jack Miller's 'aggressiveness' during the Australian Grand Prix at Phillip Island, describing some of his overtaking passes as "crazy".

Petrucci was involved in a fierce scrap for seventh place with his Pramac Ducati team-mate Scott Redding, plus Miller, Bradley Smith on the Monster Tech 3 Yamaha, Hector Barbera and Nicky Hayden, who was riding the Repsol Honda after replacing the injured Dani Pedrosa.

Hayden was sent sprawling out of the race after a clash with Miller at Honda corner on the penultimate lap, while Barbera also slid off on the factory Ducati GP16 after becoming embroiled in a tussle with Marc VDS Honda rider Miller.

Petrucci, who finished ninth behind Redding and Smith, conceded vital points to his British team-mate as their battle continues to earn the right to ride the new Desmosedici GP17 next season.

"It was difficult to stay in front of my team-mate and in the last corner we were with four riders and I lost the position, the eighth spot, and I finished ninth. Anyway, I cannot be happy but we made a good race and we are really focused to go to Sepang," said Petrucci, who is six points behind Redding with two races to go.

"Jack was very aggressive and all the race he made some very strong passes, especially corners four and 10. I destroyed my winglet and my fairing because he was absolutely aggressive. On the penultimate lap he overtook me again and put me wide. I prepared everything to overtake Scott but it was not possible because I had to pass Jack.

"Even when I passed him, he continued to brake harder and harder and went wide and we nearly crashed. Anyway, it's racing and I lost the battle. With Smith, I didn't know he was behind, but in the last corner we were with four riders and I lost the battle for the seventh place," added the Italian.

"We want to make another strong race in Sepang and for sure today we are not happy because it was very easy to crash and Miller was like crazy. I'm happy because I finished the race."

Petrucci believes Miller deserves to be penalised for his hard overtaking moves at Phillip Island and suggested the Assen race winner would be more competitive if he "calmed down".

"I let another rider crash, [Eugene] Laverty, in Austria and I was penalised. Now, I think he has to be penalised but it is not my choice, so I don't know. At the end I was able to stay in front of him and okay it is racing, but it was very strong passing," he said.

"Maybe he has to stay more calm because he was fast and if he was more intelligent, maybe he would finish in front of me. He wants always to brake later and later and sometimes he misses the corner."