Honda duo still unsure about form

"Today has been a good day for us," said Button after posting the 11th quickest time in the afternoon session.

"We focused mainly on tyre work and getting the best out of the car in the very hot conditions. Everything went smoothly and the car feels much as it did at the Jerez test, which is pleasing.

"We won't know our true relative position compared to the competition until later tomorrow, but at the moment the priority for us is focusing on our own test items and adapting the set-up to the requirements and conditions here," added the Briton.

Barrichello, 14th fastest, agreed with his teammate and admitted the team had been conservative today, leaving the Brazilian hopeful for tomorrow.

"It is still too early to tell how we will perform in qualifying tomorrow," he said. "We ran a fairly conservative programme today and we are looking better than in testing, but Friday is not a real indicator of performance as everyone is running their own programme with regard to fuel levels.

"We aim to be in the middle of the pack tomorrow and I believe we are on course for this."