Ducati rider Jorge Lorenzo says his poor showing in the MotoGP race at Austin made him feel "very sad" and was "difficult to accept".
Lorenzo was the top Ducati on the grid in sixth, but he struggled in race trim, finishing 31 seconds behind race winner Marc Marquez in 11th.
This meant the three-time champion has only six points from the first three races, continuing his worst start to a MotoGP campaign.
"I'm very disappointed," Lorenzo said after the race. "I'm very sad. Today is not a good day for me.
"Difficult to accept this result, but there is no other way than [to] forget this race, think positive, keep working very hard, as I'm working now.
"The results for the moment are not coming, I just hope that the things change and I can demonstrate my riding."
The Spaniard said he struggled throughout the race but "especially in the end", and explained that "a lot of problems" contributed to his abject performance.
"Firstly, [it's] difficult to start with the new bike, a little bit more than last year.
"Probably we didn't choose the right tyre on the rear - the hard [compound] was spinning so much, moving so much.
"Very physical track, and with the new bike I believe that I struggle more physically, especially in the braking. [We] have to find some solution for the future.
"Very sad, very disappointed to finish to so on the back, so far from the top guys."