The German manufacturer bounced back from a front-wing failure on the opening day at Jerez to show an impressive level of reliability with its new car, even completing a race distance.
That performance was in stark contrast to potential title rival Red Bull, which endured a nightmare test thanks to a spate of cooling and power unit problems that meant it completed just 21 laps.
But although Mercedes' form was better than even it expected, team chief Toto Wolff was keen to play down talk that it had stolen a march on the opposition.
Mercedes wins the phony war
When asked what his reaction was to those who suggest Mercedes is clear favourite after Jerez, Wolff told AUTOSPORT: "I think these people should look at the past.
"Very often the so-called favourites after the first couple of days of testing were not the favourites when the season actually started or panned out. It is too early right now."
While buoyed by what Mercedes achieved at Jerez, Wolff made it clear that no team had shown off its full performance yet.
Ten things we learned from Jerez
"I would say we are cautiously satisfied," he said. "We thought that we could be running into more problems than we actually did with the whole new concept.
"It looked difficult on the first day of testing, but in the end the car seems to be running reliably.
"We cannot judge performance yet - we are far away from performance, far away from what we think what our potential is.
"There are still little bits and pieces missing, and not functioning in the way we want them to function.
But we are cautiously optimistic and it looks like the guys have done a good job."
COOLING STILL A CHALLENGE
Wolff reckoned that the next test in Bahrain would prove more significant for finding out how well Mercedes had adapted to the regulations.
He cited cooling as a key area that was not challenged as much at Jerez as it will be during the season.
Gary Anderson's Jerez test review
"The data we have acquired shows that cooling is going to be an issue," he said.
"Even at Jerez, with the ambient [temperature] being quite cold, we were experiencing a high level of temperatures and challenges on the cooling side.
"We have seen for some of our competitors it is even more. Certainly Bahrain is going to be a very interesting new experience in terms of cooling levels. This is going to be one of the main challenges of the season."
HOW THE MILEAGE STACKED UP FOR MERCEDES
F1 teams had been bracing themselves for a tough time at Jerez as they got their first track taste of the new 2014 turbo engines.
In the end, Mercedes had plenty of reasons to feel satisfied with just how much mileage it completed with the works cars of Lewis Hamilton and Nico Rosberg, plus customer teams McLaren, Force India and Williams.
A comparison of its performances from the last five years shows how the distance covered in 2014 was not much below what it had achieved in recent years - and even better than the first years of the new Silver Arrows.
- Toto Wolff