Lewis Hamilton blamed his decision to switch to an older rear wing for a "disastrous" Spa qualifying result.
The McLaren driver described his eighth place in qualifying as 'damage limitation'.
Hamilton won last time out in Hungary but believes that his choice not to use McLaren's new rear wing rules him out of contention for victory in Sunday's race at Spa.
Hamilton and the team made the decision to use the old wing after struggling in Saturday morning practice, believing that it would be faster in qualifying.
However Jenson Button decided to stick with the new wing and took pole position.
"It was a disaster for me, but we are still in the top 10 so it is damage limitation for me. It was literally all down to the rear wing," Hamilton said.
"I was told the difference in wings was not so great, so it is definitely a surprise. I was told that in qualifying my wing would be quicker but for some reason it wasn't.
"It would be great to be up there fighting for a one-two tomorrow but with the wing I have that is not going to happen. The quick cars will be quick in the race tomorrow.
"Jenson's wing is working perfectly for him. It's great for him and I hope he gets maximum points tomorrow."
Hamilton said he got everything out of his McLaren in his chosen configuration.
"Nothing happened on my lap, I got absolutely everything out of the car on all of the laps that I had generally," he said.
"The set-up might not be perfect but I can't make up the time that I lose on the straights."