Sergio Perez admitted that he was lucky to escape without injury from his Malaysian Grand Prix accident, in which debris from another car penetrated his cockpit.
The Mexican appeared to be on course for another points-scoring finish in Sepang, but was forced out of the race when his car stopped after being struck by a part from another competitor.
It was only post-race examination of the car that revealed just how fortunate Perez had been, with what is suspected to have been ballast from another car having gone through the tub and entered the cockpit. The damage to the chassis meant it could not be used again, so Sauber has prepared a new tub for Perez for the Chinese GP.
"I think it was something very unsafe," said Perez in China. "I was really lucky to get away with no damage (injury) after we saw what had happened to the chassis.
"It came through very easy, so I am happy that nothing else happened to me. For this weekend we have a new chassis. We didn't see what part it was. We reckon it was ballast, as nothing else could do such damage."
Perez said he did not have time to avoid whatever he hit, and that his team does not know exactly whose car it had fallen from.
"Something was there on the track – we don't know if it was from a Toro Rosso or another team. When [Jaime] Alguersuari drove into it, it just came straight at me and into my car. It was a very dangerous situation because it came into the computer software box and it stopped just before my seat."
Despite the disappointment of Malaysia, Perez is pleased with his early season progress, and reckons Sauber can regularly challenge for points.
"I think the team is doing a great job," he said. "We had a good start to the season, but were a bit unlucky in the last race for me. But still, we were in a good position for points and I am looking forward for this weekend. I hope we can score some good points."