Sutil's spinning car backed into the side of Webber's Red Bull as he turned in at Turn 3 following the first safety car restart.
The Red Bull was soon ablaze as Webber pulled up in the run-off area.
"I think the KERS caught fire very quickly because the contact was very high," said Webber. "I think it was an immediate KERS fire."
It took some time for the fire to be brought under control, with the safety car then required after a fire vehicle abruptly appeared on the circuit.
"The fire got quite heavy quite quickly, so it was good that the guys weren't too far away," Webber said.
"I would've liked to get somewhere a bit closer to an extinguisher but I wanted to get out myself."
Webber confirmed that he had made his own efforts to put the fire out and had no qualms about doing so.
"I tried to put it out - there's an extinguisher in the car," he said. "I've got my [fireproof] overalls on."