Kamui Kobayashi admitted he was baffled as to why his Sauber team struggled to get its tyres working in qualifying for the Hungarian Grand Prix.
Kobayashi, who finished in fourth position in the previous race in Germany, was knocked out in Q2 after Sauber continued to struggle for pace at the Hungaroring.
The Japanese driver, who said it would have taken a miracle for him to move into Q3, said he was not surprised to have finished in 15th position.
"Well, after we have been struggling in all free practice sessions since we got here the qualifying result doesn't come as a complete surprise," he said. "To me getting through to Q3 would have been a miracle today.
"We don't understand why we can't manage to get the tyres to work at this track, and this goes for both compounds as I can't find the grip I need.
"Perhaps it is track related and has to do with bumps or dust or even something else. It will be another tough race for us because overtaking is particularly difficult here, but certainly we won't give up and will try our best tomorrow."
His team-mate Sergio Perez completed a low-key day for Sauber, the Mexican winding up 14th, which he believes is the maximum he could have hoped for.
"Basically this was all that was possible for us today," he said. "For some reason all weekend we have been struggling with the balance of the car and how to understand how the tyres work on this track.
"I feel on my car we made a big step forward in regard to the balance between free practice this morning and qualifying. Q1 actually didn't look bad at all, but the car still behaved inconsistently and in Q2 it was so difficult to put a perfect lap together that I didn't make it into Q3."