As testing came to an end on Sunday it was understandable that Red Bull had a lot more to smile about than Mercedes.

However, much like McLaren, which also had an impressive three days, the Milton Keynes outfit opted for quietly confident as opposed to punching the air in the belief that it might finally have the upper hand.

After all, this is testing, and come season end when the trophies and prize monies are handed out won't count for anything.

Cast your mind back twelve months, before Mercedes went on to claim its seventh successive brace of titles, when headlines such as 'Hamilton concerned at reliability' and 'Ferrari quickest as Mercedes falter' were the order of the day.

Admitting that it was his team's best pre-season test ever, Helmut Marko is taking nothing for granted and fears Mercedes has yet to show its hand.

"That was certainly the best test since Red Bull Racing came into existence," he tells German broadcaster RTL. "Everything worked right from the start.

"But we know that Mercedes is the favourite," he continues, "and I assume that they drove with much more fuel than we did.

"The fact that they didn't really align with others in terms of fuel load, already shows that they must have a lot of confidence. So we assume they still have a lot up their sleeves.

"Mercedes is the favourite," he insists, "and we are the first challenger. That's how I see the situation.

"Behind them, it's going to be a battle," he admits. "I think McLaren will stand out a bit, but not at the level of Mercedes and us. The midfield is certainly closer together."

While the Mercedes appeared unstable, causing moments for both Lewis Hamilton and Valtteri Bottas, Marko is confident that Red Bull has got on top of the aero issues that made the RB16's predecessor a handful last season.

"Compared to Mercedes, our car definitely seems calmer," he says. "Of course, that makes it easier for a driver. It's predictable, and you can work better at the limit. But that was the goal. We didn't want to make the car slower so that it's easier to control. We wanted a fast car that is predictable. And I think we achieved that well."