It was a rollbar failure that wrecked Sebastian Vettel's hopes of securing pole position in the final moments of today's qualifying session.

"Q1 and Q2 were very smooth," said the German after the session which saw his teammate Mark Webber score his third successive pole position, "I was happy with the car and there were no problems. In Q3, the first lap was brilliant up to Turn 12, then under braking I slightly locked the front which was no issue, but it was very weird as the inside front just kept locking and never came back. Going into Turn 13 I was turning to the right and the wheels started turning again and then the same thing going into Turn 14. I locked the inside wheel very easily, the car didn't seem to stop, so I lost time.

"On the second run I got confirmation in the first turn that there was a problem, as I hit the brakes and went straight - I lost the ability to stop the car and the inside wheel didn't do what it was supposed to. In Q1 and Q2 we were on top of the game, but in Q3 we were not, so it's quite frustrating."

The team subsequently traced the German's problems to the rollbar which failed at the end of his first flying lap in Q3. Under braking, the left-front wheel would have lifted, thereby giving Vettel the impression that the cause was brake related.

The rollbar can be replaced under parc ferme rules without the joint championship leader suffering any penalty. However, the failure once again highlights the Austrian team's reliability issues.