Feb.28 (GMM/Inautonews.com) After a winter of apparent ‘sandbagging’, Mercedes finally let the cat out of the bag on Friday.

Team boss Toto Wolff, however, denies that the ultra-dominant reigning 2014 champions have been hiding the potential of the new W06 car until now.

“Our programme was planned from the beginning,” he said.

“Other may have done it a bit differently to us. We estimate that we should still be ahead” in 2015, Wolff acknowledged.

As far as Mercedes’ rivals are concerned, the Austrian can say that again — and again.

Nico Rosberg utterly humbled his competitors on the second day of the final winter test, leaving second-best Valtteri Bottas more than a second behind.

And the German was using only the soft Pirelli, not the even quicker super-soft.

Williams’ Bottas was blown away.

“Everyone knew they were quick,” said the Finn, “but they were very quick. But that’s how it is.”

Earlier, insiders were wondering if a grandee team like Ferrari had managed to substantially close the gap to Mercedes in just one winter.

The Italian squad has always played down that prospect, but after seeing Rosberg’s pace on Friday, Sebastian Vettel said the headline laptime was in fact “awesome”.

And Jenson Button, despite McLaren-Honda having its best day of the winter on Friday with over 100 laps, said the Mercedes pace was “unbelievable”.

As for Mercedes picking up in Melbourne where it left in Abu Dhabi three months ago, Vettel said: “Anything else would be a huge surprise.

“What will happen behind them,” he added, “is less clear.”

Meanwhile, Force India’s long-delayed 2015 car finally made its debut on Friday, duly completing 77 laps in the hands of Nico Hulkenberg.