Sauber team principal Monisha Kaltenborn believes last week's first pre-season test in Jerez provided only "a snapshot" of what can be expected come the opening grand prix in Australia next month.

The Swiss-based marque enjoyed a reasonable run in southern Spain, completing 163 laps in total, with only Mercedes, Ferrari, McLaren and Williams ahead of them.

In light of the major regulation changes and the introduction of new power units and energy recovery systems, Kaltenborn has declared herself "satisfied" with how Sauber fared.

Given the C33 was only ready "just in time", Kaltenborn added: "The fact the car functioned from the first day on track is a remarkable achievement by the team.

"The cars are very complex this year because of the new power unit, but, as a matter of fact, we have reached a good level already."

Appreciably there were issues, and as Kaltenborn rightly concedes, there is "room for improvement" given the new systems are in their infancy.

It is why Kaltenborn is refusing to read anything into the lap times posted at Jerez, adding: "It's very difficult to judge because every team ran a different programme, including different fuel loads.

"The tyres were another important factor to consider. Both our drivers struggled to get temperature into them.

"And it certainly didn't help them we only had a provisional aero package with limited downforce on the car.

"However, this didn't come as a surprise to us. We know what to expect.

"It was our top priority to be ready from the first day of testing, to be able to drive and collect as much data as possible."

Sauber are planning on an updated aero package more relevant to the first race in Melbourne for the next test in Bahrain later this month.

But it is the power units that will prove the key differentiator in the first part of the season, with Mercedes appearing to be ahead of Ferrari - who supply Sauber - and Renault.

Despite that, Kaltenborn said: "Again, it is very difficult to judge at this stage.

"The only thing you can place in an order is the number of laps the teams did with the respective engines. Here the order is clear: Mercedes, Ferrari, Renault.

"But to compare the performance is impossible at the moment, also because some might still be playing their cards close to their chests.

"I am sure there will be movement right up to the first race in Melbourne in that regard. At the moment this is just a snapshot. It will remain exciting."