Red Bull feared Vettel would retire from the Brazilian GP

Red Bull feared that Sebastian Vettel would be forced out of the Brazilian Grand Prix as the result of his opening lap clash with Bruno Senna.

The German was spun after colliding with Senna on the entry to Turn 4, and he was hit again by the Brazilian when his Red Bull was facing the wrong way.

The contact badly damaged the rear bodywork of Vettel's Red Bull car, and left team chiefs on the pit wall worrying that their title chances were about to be derailed.

When asked if there was concern that the damage was big enough to cause Vettel to retire, team principal Christian Horner said: "Absolutely.

"There was quite a lot of damage to the exhaust and they're sensitive bits of equipment. So for them to receive an impact like that, of course, it was massively concerning."

Red Bull technical chief Adrian Newey believed that the damage to the car was at the absolute limit of what it could take.

"It's probably about as bad as you can possibly have and still finish the race," he told AUTOSPORT.

Newey was seen studying close-up images of Vettel's damaged car on the pit wall in the early stages of the race. He revealed that the team had to react at various stages of the race to ensure that the damage did not get worse.

"We monitor the loads through the pushrods, as I'm sure all teams do, so we could see that we had lost downforce, particularly at the rear," he added.

"At the first stop, we adjusted the front wing slightly.

"But you're carrying that lack of downforce because there's nothing you can do about that.

"Then the other big concern was the crease that we could see in the exhaust system.

"If the exhaust breaks, which there has to be a high probability of with that sort of damage, it would probably catch the bodywork on fire at that point and your race is over.

"So we changed the engine mapping to try and minimise the exhaust temperature. We lost a bit of performance in the process and just tried to get it home."

Despite the damage, Vettel secured a sixth place finish in the Brazilian GP that was good enough for him to secure his third straight title.