Stoner had earlier run-off at the end of the back straight after missing his braking point on lap 3 of 27, dropping him to the tail of the field at a track where his Ducati had already been struggling.
The young Australian then fought his up to the tail end of a group fighting for fifth position and was trying to pass Nakano for tenth when the incident occurred - once again at the end of the back straight.
After his second trip through the
Jerez gravel, Stoner eventually finished eleventh - his worst ever result as a Ducati rider - and has dropped from first to fourth in the 2008 world championship standings after round two of 18 rounds.
"Today wasn't my day - I suppose it wasn't my weekend," reflected Stoner. "We never found the set-up here that would let us make the most of our potential. Normally braking is one of the strong points of our bike but here I just didn't have the feeling with the front. I wasn't quite on the limit when I ran off track the first time but I couldn't get the bike stopped so it took me by surprise because we weren't doing anything differently.
"After that I had to really push to get back into the race and I was pretty happy once I caught the group. Just when I was passing Nakano he let go of the brakes and touched my wheel, so I had nowhere to go but the gravel. I think I could have finished fifth, which I would have been happy with, but instead it was a bit of a disaster.
"The tyres weren't perfect but they weren't bad either so I can't blame it on that. I'm not happy but it's not the end of the world - there are plenty of other tracks and other races, starting with Portugal [next time out], where we went well last year and finished on the podium, even if we had some little problems, and where this year we will try to fight for victory."
