Technical director Adrian Newey admits that he felt Sebastian Vettel's hopes of a third straight F1 title had come to an end when the German was involved in a clash on the opening lap of the Brazilian Grand Prix.

Having made a poor getaway when the lights went out, Vettel was then tapped into a spin by Bruno Senna at turn four and collected by the Williams driver as his car span back across the circuit.

The second contact damaged the rear left of the Red Bull and led to nervous moments on the team's pit gantry before it became apparent that the German would be able to drive around the problems created and keep his title hopes on track.

In challenging conditions after the anticipated rain arrived, Vettel was able to bring his car home to the finish in sixth spot to secure a third straight championship title but Newey admitted he thought the lap one incident had been the end for the team's hopes and said he was surprised when Vettel was able to keep going.

"To be perfectly honest after the first lap I thought it was probably all over," he told Sky Sports. "I was pretty surprised to see the car going. Sebastian radioed in thinking he wasn't going to be able to get going.

"We then photographed the car going past and saw all the bodywork damage, and more worryingly almost, a huge crease in the exhaust system. Normally that sort of damage the exhaust is going to crack and the bodywork will catch fire and that will be the end of that."

Newey added that the team had been forced to change its approach to the race in order to deal with the issues created by the accident, with the loss of Vettel's radio also making it more difficult.

"All we could do was change the engine mapping to keep the exhaust as cool as we could," he said. "We obviously lost performance with all that damage which is why in the middle stint we put him on the hard tyre hoping that would last longer but of course with all the damage the balance of the car was so good.

"So he went to the point where he had to come in because the tyres had gone but we knew it could rain any minute. But as usual you can only put on the tyres that are appropriate for the weather conditions - you can't rely on the weather forecast.

"And of course one lap later it was raining and we needed intermediates. But by then the radio had gone, Sebastian arrived in the pit lane unexpected and wanting intermediates."