Barrichello didn't expect Button's pole

Barrichello had looked like the faster of the two Brawn drivers until the final seconds of qualifying at Catalunya, when Button jumped from a provisional eighth on the grid to first place with an astounding last-gasp run.

"I was very, very happy with the car in Q2, and it came to me as a surprise," said Barrichello of Button's pole run.

"It was a great effort from Jenson, he is doing a great job and deserves to be there."

The Brazilian was the first of the main contenders to complete his final flying lap, and suspected that Button's ultra-late effort - the championship leader crossing the line just two seconds before the chequered flag fell - played into his hands.

"I had a good lap, I may have been a bit early on the track and that is the only missed opportunity," Barrichello said.

"The lap was good, well within the limits."

He remains confident that he can take the fight to Button in tomorrow's grand prix.

"We have a good car for the race," he said. "I am still fighting. Jenson is really doing well at this minute and I just have to try harder to try and get him."