Other than a lap which finally revealed what Williams might be capable of this year, the opening day of the final pre-season test was a pretty low key affair.

However, whilst the Grove outfit finally began to show its hand, world champions Mercedes was having problems, the German team throwing in the towel early following an MGU-K failure.

Talking of MGU-K's, it was another torrid day for McLaren, the Woking outfit side-lined by a hydraulic leak after just seven laps.

After a nice bright, crisp start to the day, which saw many of the cars present looking slightly different to how they looked less than a week ago, a rain shower put a damper on things around an hour before lunch.

As the teams focus of their various updates, Toro Rosso running what (technical director) James Key claims is a new car, the order of the day was checking out the updates as opposed to race simulations. That said, Marcus Ericsson went for one in the afternoon.

There were just two red flags, the first early in the session when Daniil Kvyat ground to a halt in the pitlane, and the second when Carlos Sainz stopped on track (T10) around an hour after the break.

Whatever the problem was it saw Sainz miss much of this afternoon's running, the Spaniard not reappearing until twenty minutes before the end of the session.

Indeed, compared to last week, when we witnessed most of the drivers completing in excess of 100 laps, only two reached the 'magical' figure today, Ericsson and Massa.

While McLaren announced that its day had ended early (again), attention turned to McLaren, where Lewis Hamilton hadn't been seen since the lunch break. With two hours remaining, the German team revealed: "Failure in the hybrid system keeping us in the garage currently. Crew working hard to fix it as we speak."

An hour later, it added: "That's our day done. Problem diagnosed as MGUK failure. Crew working hard to make sure we're back in business tomorrow."

All-in-all a low-key day, the eight drivers completing less than 600 laps.

Massa's time is staggering, especially as it came on the soft rubber, leaving us wondering what Mercedes might be capable of.

Whilst there were late improvements from Ericsson, Grosjean, Raikkonen and Sainz, only the Swede was able to get anywhere near the Williams, and even then only with the aid of the supersoft rubber.

As the countdown to Melbourne continues, tomorrow hopefully sees the track debut of Force India’s 2015 contender.

"It was a good day for us and the car behaved well," said Massa. "When we tried to use the new soft tyre we managed to get some quicker laps in. The FW37 never showed a sign of an issue and this has been the case since we arrived at the first test in Jerez. We are doing a lot of work and seem to be moving forward. I have just one more day in the car before the first race, so Saturday will be important."

"The programme was slightly upset by the rain in the morning," admitted Rod Nelson, the Grove outfit's Chief Test & Support Engineer, "but that just meant we had more work to do in the afternoon.

"We managed to complete the planned schedule though and we have made some positive changes to the chassis, as well as some aero adjustments. We are now looking at what we will take to Australia to make sure we are prepared for the first race. It has been a good day, with no reliability issues."

With Marcus Ericsson at the wheel of the C34, Sauber spent the morning carrying out aero measurements and practice starts. After the lunch break Ericsson went through a race simulation and finished the day with short-runs. The Swede was the busiest driver of the day, completing 122 laps in total.

"It was a productive day," said Ericsson, "and for me the best one of the pre-season so far. The morning went well until the rain came, which forced us to slightly change our plans. In the afternoon we planned a full race simulation, which was a very good exercise for the team to get valuable data. Also for me it was important to get a feeling for the 2015 tyres over a race distance with different fuel loads. We finished the day with short-runs on soft and supersoft tyres. Overall, a positive day during which we have learned a lot. I hope we can continue for the rest of the week in the same way."

"It was a good day for us," added Giampaolo Dall'Ara, the Swiss team's Head of Track Engineering. "We completed a race distance and also did short-runs with a bit of a shuffled programme due to the unexpected shower before lunch. In the end it all went well, as we were able to complete the programme."