Although Mark Webber and Nico Rosberg were not explicitly pointing fingers at one another for the collision that ended a dismal season for Williams on perhaps the lowest possible point of the year, neither were quite in agreement as to why they came together on the first lap of the Brazilian Grand Prix.

In a typically fraught start around the first turns, Rosberg appeared to lock up into turn three, slamming hard into the back of the sister car of Webber, the Australian coasting round minus a rear wing to the pit lane to retire in his final race for Williams.

Rosberg though attempted to make it back to the pit lane but instead suffered a puncture as he came over the hill for the start of the finishing straight, careering to the right and hitting one of the circuit's fearsome walls, destroying his car in the process.

However, although neither driver was willing to blame one another for the initial incident, Webber believed Rosberg had missed his braking point, while Rosberg instead counters that Webber braked earlier than he had needed to.

Indeed, Webber was particularly aggrieved as it was a race in which Williams could have been fighting for points. As it stands though, Williams end the year in a very disappointing eighth place overall, leaving Webber to now look forward to his switch to Red Bull.

"Such a waste," he said. "It was an interesting first few corners, I was fighting with Jenson and Pedro going into the first one and putting a bit of pressure on Pedro. It was shaping up to be quite fun, but I braked a bit later going into turn four and then I was hit from behind. I lost the diffuser and that was that.

"It looks like Nico lost his braking point. He was very deep going into the corner and I didn't think he was going to make it. It's always bad when team mates collide, but he didn't do it on purpose. This is the game we're in, there are no rewind buttons, so when it goes wrong, it goes wrong. This isn't the result we were hoping for and it's a real shame for the guys."

Rosberg meanwhile emerged from his heavy crash unhurt, nursing his pride somewhat in a debut season that began on a massive high in Bahrain but ended with something of a whimper.

"I was really hoping I could do something good in the last race. After the start, I was trying to get out of traffic, gain some ground and get back the place I had just lost to Jenson so I was close behind Mark going into the corner. I think he braked hard and maybe an extra metre too early, perhaps because something had happened next to him, and I hit him.

"It probably seemed a big accident from the outside, but it didn't feel so hard in the cockpit and I am fine. I am sorry for the team, of course, because I wanted to finish this season in a better way. It has been a difficult year, but I have learned a lot. We now have the winter ahead of us and we will all work together very hard to be prepared for next season."

Still, despite a disappointing season Williams are determined to go into the winter with their head held high as they herald a supply of Toyota engines, a new title sponsor and a revised driver line-up of Rosberg and Alex Wurz.

"It can only get better from here, but obviously the result is massively disappointing," said Patrick Head. "The Bridgestone tyre was quite clearly superior today. It's meaningless, but I think we could have had quite a good race.

"This is the second year in a row in Brazil that we've been out of the race with both cars before the end of the first lap and it's really very disappointing for everyone in the team. However, we can now only go back and make sure we have a much better car and look forward to a stronger season next year."