Hamilton slumped to eighth in the race after running as high as third in the early stages.
Mercedes’ tyre wear issues continued, meaning Hamilton was the first of the leading group to make his first pit stop.
Embarrassingly for Mercedes, Hamilton even lost out to Alpine’s Pierre Gasly in the final stint, meaning they had the sixth-fastest car at Interlagos.
It capped off a tough day for the team, with George Russell failing to make the chequered flag.
“It didn't feel as disastrous as yesterday,” Hamilton said. “Yesterday I literally had no tyres left, they were worn to zero. I feel like I drove a better race today in terms of managing the tyres to the best of my ability.
“But the car, there's moments it works and moments it doesn't, and it's so inconsistent through the lap. So we have to figure out what that is.
“Then also we are really slow on the straights and at least sliding the car through the corners. So one to forget but hopefully there's lots of learning from today.”
Hamilton conceded there just being one practice session ahead of qualifying made life more difficult for Mercedes.
“One thing the car is really unpredictable,” he added. “In a sense of one weekend it feels good, one session it feels good, and then not. I'm sure we will go and look at things and find things we should have done differently but with the one session it's difficult.
“But I'm still proud of the team, they still came here and did their work, they held their head up high and that's what we have to continue to do. Just keep pushing forward. Two more races with this thing and then hopefully no more driving it.”