Mercedes has admitted that it is 'worried' rival Ferrari is on the verge of a Formula 1 breakthrough that could derail its current dominance.
Although Ferrari has been unable to repeat the kind of form that helped Sebastian Vettel win in Malaysia, it has been pushing hard to close the gap to the front.
And that is why Mercedes motorsport boss Toto Wolff says his outfit is paranoid that its advantage could suddenly be wiped away, as he fears Ferrari could make the kind of leap his team made after 2013.
"We can't afford ourselves to be complacent and neglectful, because if you are there is a big chance you don't develop your car and your team so can't follow this winning way," explained Wolff.
"That's why you have to keep same pressure in the system. When you have Ferrari [as a competitor] with all of the resources they have, the day when we would not be able to win any more can come very soon.
"This cannot happen from today to tomorrow, but this can happen slowly if you are complacent."
He added: "We see every now and then glimpses of performance from Ferrari which shows that they develop.
"We see their performance during sessions; we saw their long runs on Friday and on Saturday morning when their pace was better than ours. And this disappeared in qualifying.
"I can see parallels with 2013 when we also had sessions like this or races where we showed good performance, but just couldn't maintain this.
"And because of that as well, when I see this kind of performance of Ferrari, I'm always worried."