Even though he had a good lap on the soft tyres, Jenson Button has revealed his MP4-29 is generally lacking balance around the Hungaroring.
The McLaren driver completed 60 laps in Friday's two session with a best time of 1:26.234.
That time, set in the afternoon on the soft Pirelli tyres, put him ninth on the timesheet, 1.752s behind pace-setter Lewis Hamilton.
"I had a relatively good run on the soft tyre using high fuel, so I'm feeling happier about that, but the balance over a single lap is something we need to concentrate on tonight," Button revealed.
"It was quite difficult to be consistent; the car felt different from corner to corner, from lap to lap. I like a precise car, and we didn't quite nail that today - but I think we know why that is and we'll change it for tomorrow. I'm not too worried."
And although both McLarens were inside the top ten on Friday, Button is wary about whether that is their true position in the pecking order.
"Looking at the timesheets, it's quite difficult to know where we stand," he said.
"We're not up there with the Mercedes or the Red Bulls, but the Williams cars seem a little less competitive compared to the last race."
He added: "We still have a lot of work to do tonight."