With two Hamiltons, the team would explode - Wolff

Toto Wolff has denied that Mercedes spent much of the 2015 season 'sandbagging' to hide its true performance advantage. Red Bull's Daniel Ricciardo said recently that amid talk Ferrari now seems poised to mount a title challenge for 2016, he thinks Mercedes is still a long way ahead. "Ferrari caught up a little bit," said Ricciardo, "but I think in general when they (Mercedes) wanted to turn it on they could."

Mercedes boss Wolff, however, said on Thursday: "There were races where we looked after the cars, when it was not necessary to go full blast. But these were the exceptions rather than the rule. In most of the races, we had to show our full potential in order to win, and in Singapore we saw clearly that it wasn't enough," he told Auto Motor und Sport.

And so Wolff says Mercedes will head into next season treating Ferrari in particular as a very real championship threat. "Our philosophy is to be permanently sceptical," he said. "In all areas we have very ambitious development objectives that we want to achieve, but that does not protect us from losing another part of our lead if our competitors do a better job."

The Austrian also admitted that a lot of attention after the season concluded went into working out why Lewis Hamilton's performance suddenly slumped, just as Nico Rosberg rounded out his year with three wins from pole. "We are a bit cleverer (about it)," said Wolff, "but not much. I think a major role is the psychology."

"Lewis has achieved his goal, bagged the title and then relaxed a bit," he said. "Although perhaps only subconsciously. At the same time I don't want to detract from Nico's performance, which was great. It shows we have two drivers who will be driving at peak performance for us next year, which is the key to success even though it caused us a few grey hairs."

Indeed, Wolff's grey hairs prompted him to warn recently that if the growing animosity between the drivers spills into the 'spirit' of the team, Mercedes would have to think about changing the lineup. But he clarified now that Mercedes remains happy with Hamilton alongside Rosberg.

"If we had two Hamiltons, the team would have probably exploded," he smiled. "But two Nicos wouldn't make it easier either. The combination of the two is quite good. It is the ideal situation, even if it makes life hard for us sometimes. But precisely because they are so different, with individual approaches, it helps us to be better," said Wolff. (GMM)