Casey Stoner apologised to his Ducati team after crashing out for the fifth time in a 2010 MotoGP race, at Estoril on Sunday.
The Australian was running third on an unfamiliar dry track, after a weekend of rain, when he lost the front of his Desmosedici on lap 5 of 28.
The crash means he has lost third in the world championship to Valentino Rossi, and will need to score twelve points more than the Italian in this Sunday's Valencia finale to reclaim the position.
“There is not much to say today, other than it's a shame, obviously," said Stoner.
"I was taking it steady over the first couple of laps getting the tyres up to temperature and then I was able to push a little harder to close the gap to the guys in front of me.
"When I got on the back of Jorge I wasn't pushing as hard as I had on the previous laps but I ran a little off line and lost the front.
"I tried to save it but I wasn't able to and I am really sorry to all the guys in the team because they have done a good job in difficult conditions to find a good set-up. We will try and make up for it in Valencia.”