Toto Wolff, the team principal of Mercedes Formula One, said on Tuesday (1 December) that the team will retain its practice of having two number one drivers. Mercedes has been dominant for the past two seasons, with Briton Lewis Hamilton winning the championship both years, and his German teammate Nico Rosberg finishing second on both occasions. In the 38 races over the past two seasons, Hamilton has won 21 races and Rosberg has won 11, as they have swept the constructors' championship both times as well.

Despite the results, the relationship between the drivers has appeared to be difficult at times, and Wolff, speaking at a media event in Malaysia, said that while achieving the correct balance for each driver was not always easy, it was the way he wished the team to proceed.

"It is not always easy. We have to take into account a conscious approach of having two number one drivers and we are trying to give them equal material, equal opportunity. This is a new approach; we have seen in the past, teams have been having a clear number one and a clear number two and if it was getting tough, it was clear who was getting the opportunities and we are not doing this.

"And the management of the situation is not always easy, because to manage the personalities, to manage the outcome of the race in such a way that it is not detrimental for Formula One, that you keep all opportunities open for both drivers, but again, it is what we opted for, we are going to continue to cherish that."

With Hamilton having clinched the title with three races remaining, Rosberg finished the season strongly, winning the last Grands Prix. Wolff is keen to investigate over the winter why this happened and see if they can raise the performance of Hamilton's car.

"The cars are always exactly the same, the same specification, the driver can decide if he wants to opt for different set-ups as part of the process over the weekend where you try to optimise your car. Sometimes, the set-ups merge, and it ends up with the same set-ups – sometimes they take different paths. Most recently, Nico has been benefiting a little bit more about how the car was being developed over the last couple of races, and just over the winter, we have to find out now why that was and how we can optimise the car for Lewis as well," said Wolff.

One team that has started to emerge as serious challengers to Mercedes is Ferrari. Following a dreadful 2014 – in which they failed to finish higher than third in any race – Germany's Sebastian Vettel won three races in 2015 to help the team finish runner-up in the constructor's championship.

"I think that Ferrari has done some good developments on their car and they have made a big step up from 2014 to '15, Their learning curve was a bit steeper during that winter. I have no doubt that they will be a close competitor next year," said Wolff.

Despite Mercedes' dominance over the past two seasons, Wolff said he would be a fool if he expected it to continue. "If you expect your team to dominate, you are either a fool or you are not setting the targets right. You need to have that portion of scepticism and to keep yourself on your toes. We always expect the worse and we set our targets in terms of development targets high, what do we want to achieve in terms of downforce in aerodynamics, what we want to achieve in terms of weight saving, and all the other areas of development. We believe that if you set your goals in a challenging way, and you achieve them, that you put us in a position that we can be competitive, dominant is a completely different question," he said.