But on Saturday, Lewis Hamilton exploded to the top of the times with the winter's best laptime. Nico Rosberg then went even quicker in the first half of Sunday, the last day of running before the circus heads off to Australia.
"Everywhere in the paddock, respect is being shown for Mercedes," said Auto Motor und Sport correspondent Tobias Gruner.
There are, however, outstanding questions. Didn't Mercedes also show good pace before last season, when ultimately the 2012 car fell badly off the development pace?
And isn't there a huge difference between one-lap qualifying pace and the new tyre-degradation dominated grands prix?
Finally, is the W04 really a title contender?
"It's not 'no chance' and not 'definitely we will'," Hamilton said. "We will definitely be able to win a race at some point."
Added Sauber's Nico Hulkenberg: "At the very least, Mercedes' betting odds have changed now!"