Sebastian Vettel topped the timesheets on the opening day of pre-season testing today, with the Ferrari-powered Sauber of Marcus Ericsson just 0.157s behind.

However, other than the fact that Kimi Raikkonen similarly topped the sheets of last year's opening day, Ferrari going on to fail to win a single Grand Prix for the first time since 1993, it is the pace and consistency of the Mercedes that really impresses, Nico Rosberg completing 157 laps.

Over the course of one thirty-plus lap run Rosberg's times barely fluctuated, the pace of the driver, at one with his car, almost metronomic.

On a day that saw a number of teams finally take the wraps off their car, the Mercedes W06 Hybrid looks to have taken up where its predecessor left off, as does the Honda-powered McLaren MP4-30. Following a disappointing outing in Abu Dhabi, the Woking car completed just 6 laps today, McLaren subsequently revealing that the car had suffered a "niggly problem".

Although late getting to work, Williams was soon on the pace, Valtteri Bottas completing 73 laps on his way to posting the fifth best time of the day, whilst Ricciardo lost time due to an engine issue.

Lotus missed today's running, the Enstone outfit flying the E23 out to Spain after firing up its Mercedes engine for the first time yesterday. The car will now undergo its build programme overnight and through Monday, with the first significant running expected on Tuesday.

Between them, the 7 drivers on duty completed 450 laps, compared to the 94 completed by the nine drivers on duty this time last year.

This being the first day of testing, we shouldn't be reading too much into the times, certainly Ferrari would be foolish to start thinking those two wins demanded by Arrivabene are in the bag. However, there will surely be some concern at Woking following a less than impressive debut for the Honda-powered MP4-30.

"Today was a good start," said Vettel. "I can't say more than that, because this is only the beginning. Everything is different, even the philosophy behind the car, when compared to what I was used to. But I immediately felt at ease within the team and the guys gave me a very warm welcome. For now, lap times aren't important: I did mine on the medium compound, but the comparison has to be made yet again with the Mercedes. They are very quick, let's just hope they are not quite as fast as last year..."

"On the one hand, I'm disappointed we didn't manage to do more miles, because of problems we encountered with the telemetry," added technical director, James Allison. "However, on the other, we saw the car make progress with the laps we did run."

"It seems the SF15-T took on board what was said about it at the launch!" smiled team boss Maurizio Arrivabene. "Joking apart, this is only the beginning and at this stage, lap times are all relative. We are just getting on with it for now and I'd rather emphasise the work done by the team, who seem to me to be very motivated, which I am very pleased about. I say "well done" to Sebastian, but we have to keep in mind that our rivals, especially Mercedes, must not be underestimated."

For one brief moment it looked as though Marcus Ericsson might go quickest, instead the Swede had to content himself with being second fastest along with the dubious honour of causing the first red flag of the year.

"It was a very good day," said Ericsson. "First of all it was great to be back in the car after the winter break. I think we have good reasons to be happy. We were able to complete a lot of laps, and we went through quite a few different small tweeks on the set-up and did all the installations needed. There were no major problems with the car, which was really the main thing. Overall it's been a good day, and I'm looking forward to the rest of the week. I hope we can continue like this."

"Today we started with a normal roll-out programme with some functionality checks, which we were able to cut to the minimum, because the car was working well from the beginning," revealed the team's Head of Track Engineering, Giampaolo Dall'Ara. "We had some longer breaks, just to do some thorough checks on the car. In the afternoon we went a bit deeper in by exploring the balance and checking some different tyre compounds. Towards the end we did some longer runs. We are happy that the car is working, and, compared to last year, we can see the improvements. Overall it was definitely a positive day."

Nico Rosberg, along with teammate Lewis Hamilton and the rest of the Mercedes team, will be feeling mighty chuffed following a very impressive performance today.

Though third on the timesheets, albeit just 0.486s down on Vettel, the W06 completed 157 laps, never missing a beat.

Today's programme comprised long runs and practice pit stops, Rosberg emerging for his first run at precisely 09:00, completing 60 laps before lunch and a further 97 in the afternoon.

"That was a great start to the winter testing," beamed the German. "In the beginning it's all about reliability and we managed to do a lot of mileage today. The guys in the factories built a complete new car and now we come here and it's working great, so the team did a fantastic job over the winter. I was able to do some good long runs on the first day and that's really amazing.

"We have such a great team and this is what makes me really happy. As a driver, you always want to find out how quick you are compared to the others - but that will have to wait until qualifying in Melbourne. The next testing days are all about making sure we know the car inside out and we've made a good start with that today."

Red Bull's RB11 made an eye-catching debut, the Austrian outfit's car taking to the track in a striking black and white livery, similar to that used to camouflage prototype road cars.

"We got going pretty well this morning and I got a few laps under my belt," said Ricciardo, who ended the day fourth fastest. "So the first impressions are good. We'll get a few more laps over the next few days, but so far everything seems pretty encouraging.

"I can feel a step forward," he continued. "I won't go into too much detail but it's there. We didn't do a whole lot of laps but definitely more than at this test last year! In general everything is behaving as it should. Obviously we had a couple of issues, but once the car is running it's all going pretty normally. A good first day, there are some positive signs there."

Commenting on the interim livery he added: "The livery's cool. It's a testing specification for us but I think it looks really good. Maybe I need a matching helmet."