Mercedes is taking the threat from Ferrari next year very seriously, admitting its main rivals has made some "clever moves" this year in order to catch up.
Ferrari will finish second to Mercedes in the constructors' championship this year, but has dramatically reduced the performance deficit it had at the end of 2014. Ferrari is confident it will be leading the pack in 2016 and Mercedes team principal Toto Wolff is expecting a much tougher challenge from Maranello in 2016
"I am anticipating a robust challenge from Ferrari because they have done some clever moves, and they have definitely caught up," he said. "You can see that even towards the end of the race in Brazil, Sebastian was not very far away when Lewis and Nico were pushing flat out. The biggest gap was seven seconds and that is not a clear cut dominant race win. I think we will have a situation where Ferrari will be a very important competitor."
However, Mercedes is well advanced in its preparations for 2016, with the last of its engine updates this year aimed at creating a platform for bigger gains at the start of next season. In Brazil it ran a number of 2016 development parts, including an 'S-duct' in the nose of the car, and Wolff said the team is currently deciding how radical next year's W07 will be.
"You can get it pretty wrong if you go for a revolution of a car that performs pretty well already. We are not quite sure yet, there is some interesting stuff being drawn and in the wind tunnel, and one of those very interesting areas was on the car on Friday in Brazil.
"It's a permanent evaluation between evolution and revolution and it's not yet clear where we want to take it, but at the moment it is just good to have secured the championship and be able to look at things."