The championship leader's Red Bull sustained serious damage when he hit the wall after losing control at Istanbul's famous Turn 8.

German Vettel, 23, then watched the entire season session - ran entirely in the dry - from the pits.

"The car is badly damaged and from a safety point of view we need to check everything," team boss Christian Horner told German broadcaster Sky.

"We would rather be on the safe side, checking everything three or four times," he added.