Ross Brawn fears his team's tyre-warming 'curse' has returned, despite earlier optimism that work on the BGP 001 car in Belgium had cured the problem.
Both Rubens Barrichello and Jenson Button struggled to get sufficient heat into their tires in qualifying for the Belgian Grand Prix, and Brawn thinks it shows how much more work his team needs to do before it can feel comfortable with the situation.
"It was the curse of the tire temperatures again," said Brawn. "We were struggling to get the tires to work, and obviously those teams that managed to get the tires to work made a very good step.
"With Jenson particularly, we really struggled with the tires again. On Friday it didn't look too bad, but we just slipped off a little with tire temperature. Our curse has slightly returned - not as bad as it could have been. On fuel, with a longer run it's not bad. For qualifying we struggled."
Brawn believes that Button's recent struggles, having been edged out by his team-mate in recent races, can be attributed to his smoother driving style.
"He's inherently quieter on the tires," he said. "Normally that's an advantage but in these circumstances he struggles a bit more. He's quite a smooth, gentle driver which is normally a benefit. But when we are on the edge of getting the tires to work, he seems to struggle a bit more.
"I think that it is just using the tires. The approach of how you use them and getting the tires to work in these circumstances. Perhaps it's no accident that four of the oldest, most experienced, drivers in F1 are at the front of the grid."
Despite the difficulties in qualifying, Brawn thinks that Barrichello, who starts fourth on a light fuel load, can still deliver a strong performance in the race.
"We're pretty light on fuel to try and compensate," he said. "But Rubens is pretty good at starts and he doesn't really have any KERS cars around him this time, so if he can make one or two places on the start he'll have a very strong race.
"The middle period, which will almost certainly be on the hard tire, he will be very strong. The start and the middle part of the race will be crucial."