Had it not been for the rain shower that hit the Circuit de Catalunya around forty minutes before the lunch break, and which finally cleared up almost forty minutes after the break, we might well have seen today's mileage surpass yesterday's. As it was, the ten drivers on duty managed 813 laps (compared to yesterday's 946), five of them in excess of 100.

Though third on the timesheets, there is no doubting Mercedes pace. "Still feeling under the weather but I'm pushing for you guys," tweeted Lewis, the Briton still managing to complete 101 laps and post a time - on mediums - that was only beaten once a couple of rivals switched to the super-soft rubber.

Fever or no fever, neither the world champion nor his car missed a beat today, leaving us to wonder what exactly the pace will be like when the German team finally opts to show its hand.

Aware of the change in the weather, Williams changed its planned schedule and instead shared driving duties between Felipe Massa and Valtteri Bottas, the Brazilian running this morning and the Finn this afternoon.

While Massa completed 55 laps this morning, posting a best time of 1:26.912, his teammate didn't post a time until the final moments of the session. Though he had completed more than 40 laps, the Finn and his team were focussing on pit stops rather than times. Which suggests that the Grove outfit has supreme confidence in its on-track package.

Having topped the timesheets on Thursday, Pastor Maldonado and Lotus will be delighted to be up there again, the Enstone outfit now running the all-conquering Mercedes power unit. That said, his best time was set on the super-softs so we shouldn't get too carried away.

A strong performance also from Max Verstappen, the Dutch youngster adding another 129 laps to his tally as he builds confidence ahead of the season. Like Maldonado his best time was posted on the super-softs. However, the team's day was slightly marred when the car ground to a halt on the main straight just moments after Jenson Button had stopped further down the straight bringing out the red flag.

Having missed much of the morning as his team tried to solve a gearbox issue that appeared late yesterday, Marcus Ericsson finally got out just before lunch. The Swedish youngster subsequently completing 53 laps on his way to posting the fourth best time of the day.

Sebastian Vettel's day got off to the worst possible start when he spun off on his out lap just moments in to the session, thus causing the first red flag of the day. Returning to the pits he admitted to making a mistake, having hit a damp patch on his cold tyres. He was soon back out again but appeared to be focussing on mileage as opposed to pace. All under the watchful eye of company president Sergio Marchionne.

Daniil Kvyat ran a number of long runs in the afternoon, though it was initially aborted after just a couple of laps due to the conditions. Nonetheless, when he was up and running the car didn't miss a beat and his times were good.

Helping out at Force India, Pascal Wehrlein had another solid day, the German youngster continuing to impress.

Though Bottas only completed a couple of timed laps he was still able to leapfrog Jenson Button as McLaren's woes continued. Yesterday's 59 laps for teammate Fernando Alonso must have seemed like a cruel joke as the Briton ground to a halt just eighty minutes into the day, causing the second red flag.

Reporting that he'd suffered a "total loss of power" he was soon back on track for a few more exploratory laps. In the afternoon he didn't appear until a couple of hours after the break, completing another couple of laps before heading back to the pits.

"After the morning session, we found similar issues to Thursday," revealed the Woking team. "We will now resume testing this afternoon with limited power to the MGU-K. A new re-engineered seal is scheduled to arrive and will be applied later this evening."

Though he did indeed take to the track again, just twenty minute before the end of the session, with just 24 laps under his belt, the Briton ground to a halt as he exited the pitlane.

All in all a good day, even if McLaren (and Honda) will be working late into the night tonight... and not just tonight.

Setting the day's fastest lap whilst he accomplished an extensive programme comprising various aero, tyre and performance simulations, Maldonado completed 104 laps.

"We achieved a lot today," said the Venezuelan, "and it was great to complete so many laps and end the day as the fastest car. Certainly, I feel much more confident in the E23 and we're learning a lot about it with all the laps we're completing. I'm able to push when needed and everything about the whole package feels a lot more together than last year, especially if you remember where we were in terms of performance and reliability during the pre-season in 2014. We still have a lot of work to do, but we're making very good progress so we're all very positive about the work being done."

"It was a productive day for us today," added Alan Permane, the team's Trackside Operations Director. "We chose to stay in the garage when it was damp outside yet we still managed to complete over a hundred laps. We've worked through a long checklist including aero and tyre assessments in the morning, then various performance assessments in the afternoons. Our aero work has been particularly productive and we're showing good correlation with our wind tunnel and simulations."