Sebastian Vettel says puncture in F1 Spa GP practice not his fault

Pirelli has brought its hardest compounds to the challenging Belgian circuit and prescribed limits to camber and pressure settings to avert the risk of tyre blow-outs.

Vettel's Red Bull suffered a blown right rear tyre near the end of a long run on medium tyres.

Asked if he could have caused the issue by excessive kerb use, Vettel replied: "I wasn't doing any more or less than I did for the 10 laps before..."

The German said he had no idea what might have triggered the puncture, but that it had not taken the shine off a day on which he emerged fastest.

"We don't know what happened yet," he said. "Basically I lost the rear right very suddenly, so we need to have a look.

"But other than that it was a pretty positive day."

Vettel's team-mate Mark Webber, who was second quickest, said he was not worried by the tyre incident.

"I think until we find out why it leaked or failed there is no real concern at the moment," he said.

"They would have called me in if there was an issue but it looked like a pretty standard failure."