Sergio Perez believes he will be able to produce an improved qualifying performance for the British Grand Prix at Silverstone, with Sauber making changes to solve the braking problems that have plagued him in recent sessions.
The Mexican was only able to qualify 15th on the grid for the last two races at Montreal and Valencia, with team-mate Kamui Kobayashi able to get into Q3 in Spain.
Perez feels the problems were down to the Sauber's brakes and believes the team have now sorted out the problem ahead of this weekend.
"I think qualifying has been quite bad in the last two races," he said at Silverstone.
"We've had fairly similar problems, so we've changed some of the stuff on the brakes to improve this.
"Even though Silverstone is a different track, with very low braking, it's still something we have to improve because we cannot afford another qualifying like we had in Valencia or Montreal. I'm very confident that this problem is sorted for this weekend."
Perez, who has won at Silverstone in British Formula 3 and GP2 in the past, believes that with a good qualifying performance he could challenge for the win.
"I think we've got a good car, so I think we are in a good position. I think we can fight for the victory and the podium at this track and that has to be our aim," he added.