Whether Felipe Massa's jaw-dropping 1:19.726 was set on fumes or not, we shall have to wait until Melbourne to discover. However, fuel loads aside, the Brazilian did manage to complete an astonishing 168 laps today.

That's only 15 laps shy of what Toro Rosso managed over the course of four days last week.

To further rub it in, Sebastian Vettel also completed 168 laps, making it clear that last week's first impressions of the SF70H were pretty accurate, it's a good car.

It was a day of low drama for Massa, who quietly got on with the job. The fast laps dealt with in the morning, the afternoon given over to a race sim, which the FW40 took in its stride.

Second quickest was Daniel Ricciardo, another driver who kept a low profile, and who, like Massa, did his fastest running in the morning.

Curiously, and not for the first time in testing this year, having posted his best time on softs, the Australian failed to improve when switching to the supersofts. Intriguingly, he later went out on ultrasofts, and having gone quickest in the first sector abandoned the lap and dived into the pits, though he subsequently fitted another set of the purple-banded tyres to give us a further tease. All the same, once couldn't help but feel Red Bull is playing its cards close to its chest.

Like a boring old man who refuses to give up his favourite pair of worn, but comfortable, slippers, Sebastian Vetter once again steadfastly refused to switch from the mediums.

The German's pace, not to mention those 168 trouble-free laps suggest that last week was no fluke, and Ferrari might just have got its act together.

Mercedes - who originated the practice - was one of three teams to run both its drivers today, Lewis Hamilton running this morning and Valtteri Bottas this afternoon.

It was a no-issue day for the German team - isn't it always - and though the Finn completed 86 laps compared to his teammate's 49, he was never quite able to match his time.

Esteban Ocon was another driver who kept busy today, the Force India driver adding another 142 laps to the VJM10's tally. Another team that had issues during the first test, this was the morale booster the Silverstone-based outfit needed.

It was a day not without its problems for Renault, another team that opted to run both its drivers. With a sensor issue necessitating an engine change this morning, thereby compromising Jolyon Palmer's track time, at the very end of this afternoon's session Nico Hulkenberg stopped on track.

Kevin Magnussen had a good day in the Haas, the Dane spending much of the morning trading times with Ocon. Based on the evidence thus far, the midfield is going to be tight this year, and Haas should be a leading light.

After last week's issues, Toro Rosso was simply glad to get more laps under its belt, and while Daniil Kvyat finished the day 2s off the pace, the STR12 did complete 83 laps, only 100 less than it managed over the whole of the previous four days.

After this morning's dramas, which saw yet another engine change for Honda, Stoffel Vandoorne was simply glad to be able to get on with business this afternoon, the Woking team looking for mileage rather than pace.

Fact is, after last week's nightmare it was hoped that this week might witness a fresh chapter, sadly, based on this morning's evidence there is still a long, long way to go.

Sauber was the third team to split driver duties.

Pascal Wehrlein made his return to the track this morning, the German having to miss the opening test as a result of back pain incurred in his Race of Champions crash.

The Mercedes protege completed 47 laps posting a best time 3.6s off the pace in the morning, but come the afternoon its was Ericsson who was in the C36.

"As planned Ericsson takes over the C36 from Wehrlein for the afternoon session," tweeted Sauber.

"As planned?" This was the first that anyone knew of the move, the intention always being that Wehrlein would drive the whole day. Therefore the question is, did the team change its plan, or did Wehrlein suffer a reoccurrence of his back pain?

With three days remaining, there are still more questions than answers, and at a time some are now turning up the wick in terms of performance, others are still trying to find reliability.

Weather: sunny and dry; air 13 degrees C – 21 C, track 16 C – 31 C

Check out our Tuesday gallery from Barcelona, here.