Sebastian Vettel says the increase in front tyre pressures mandated by Pirelli for this weekend's Italian Grand Prix is not helping the overall balance of Ferrari's SF1000.
Vettel's laborious first day of running at Monza saw the German driver clock in a lowly P19 in Friday's morning session, a performance he managed to improve in FP2 despite a spectacular spin at the second Lesmo.
Unsurprisingly, the German, who is likely racing in red at Monza for the final time in his career, described his car as "a handful" at the end of the day.
"Well the car is difficult to drive, but as I said, it's not the first time," said the four-time world champion. "So where are we lacking? I think we're losing down the straights, which is expected.
"We are lacking grip on corner entry with pretty much all four wheels. The car is sliding quite a lot , and it's a handful!
"But yeah, it's very difficult to get everything right to get the lap together. But we're trying to make it a bit better for tomorrow."
Vettel also suggested that Ferrari's pace on long runs was not helped by this weekend's greater front tyre "balloon" pressures.
"I think part of a contributor for that in the race is obviously the balloon pressures that we are forced to run at. That doesn't help," he said.
"It's far away from where I think the tyres would like to run. But yeah, we have to obviously stick to the rules and apart from that, it will be a tricky one in the race."
Charles Leclerc echoed his teammate's view on the SF1000's difficult handling in race trim, but last year's Italian Grand Prix winner was also favourably surprised by his car's qualifying pace.
"I think we expected a bit worse on the low-fuel runs but then on the high fuel we expected a bit better," Leclerc explained.
"So we definitely need to try to find something for the race, otherwise it's going to be very, very difficult.
"We seem to struggle quite a lot with the balance and the overall degradation of the tyres during the high fuel run. So there's definitely a lot of work on that
"But I am quite positive to see our qualifying pace. It was very difficult to drive on the high fuel.
"That's why I was saying there's quite a bit of work, but I'm pretty sure we'll find a solution to try and fix this."