“I just didn't have any grip on the rear and in the wet the problem was on corner entry to the apex. So my corner speed was just way too slow to make a decent lap time. I am not out there just riding around at the back.
“I was doing my absolute best and trying my hardest but it was impossible for me to go any faster with the feeling I had. It has been a tough weekend but I'll look to bounce back and finish strongly in Valencia."
Toseland will test for the factory Yamaha WSBK team at Portimao this week, ahead of his 2010 return to the championship.
Team manager Herve Poncharal is to investigate what went so badly wrong for Tech 3 at Sepang.
“It has been a very disappointing weekend and easily the worst for us this season,” said the Frenchman. “We were struggling in the dry so I can't say I was unhappy to see the rain because I thought this would give us a chance of improving our results. Unfortunately our performance was even worse in the rain and we can't be happy. Now we have to understand why we struggled so much this weekend.”