Hayden didn't see anything at Turn 1

The pair were running at the front with eventual race winner Casey Stoner at the first corner, but Hayden and Hopkins came together, which dropped them both out of contention.

"I didn't see anything, I just got cleaned out," said Hayden. "I didn't feel anything, then I just got drilled."

Hayden had run wide at the tight left hander, and as he tried to get back on the racing line he made contact with Hopkins who was on the inside of him.

"We got in a little bit hot, and Stoner was on the inside I was just following him," the world champion added. "Everything seemed fine.

"Then my legs got hit, I felt someone go straight into my side, and I just flopped around and tried to stay up and stay on it."

The Honda rider was disappointed to have a first corner accident for the second time this season, but he believes that it sums up the way his season is going.

"It was like China all over again. It's just the way my season it going. It was nothing I did, I just got cleaned out from behind."

Hayden's bike was damaged in the collision, and he eventually had to retire as he was suffering with brake problems.