Michael Schumacher says he may have "compromised" his W03 too much by opting for a wet set-up for qualifying for the Brazilian GP.
The German, who is retiring from Formula One after the last lap of Sunday's season finale, had been sixth at the end of Friday's running.
But by the end of Saturday's, he was down in 14th place after opting for a wet set-up in light of the forecast rain.
"For obvious reasons, I am not particularly happy about the qualifying session today," said Schumacher.
"We might have compromised the car too much for the rain which is expected for tomorrow and was also forecast for qualifying.
"When the drops came down just before, it looked even more likely."
Despite starting so far down the order, the seven-time World Champ is still hoping to finish his swansong with a solid result.
"Anyway, my starting position is now quite tricky, and I will have to see what we can make out of it tomorrow.
"Of course, coming from where I am does not make it easy, but I will definitely try to fight my way up the field."