The Finn spent his day focused on both some aerodynamic work and better understanding of tyres, with Mercedes clear in their intention to make up for its recent struggles with long-run form.

Despite triggering one red flag with a stoppage on track caused by a mechanical problem just before lunch, Bottas got through an intensive programme – setting his best lap of 1m31.280s in the final hour of testing as track conditions cooled.

His lap tally was in stark contrast to Vettel, who endured frustrations with a big amount of time lost in the pits.

In the morning, Ferrari discovered some hydraulic leaks during a setup change in the garage, and that meant a car overhaul which left him with a tally of just eight laps before lunch.

After getting going against shortly after 1pm, Vettel lost further time when data problems in the garage left engineers without telemetry and he had to stay in the garage until the issues could be rectified.

In the end, Vettel managed to get more more running done later in the afternoon to set the second best time of 1m31.574 seconds.

Toro Rosso's Carlos Sainz ended the day third fastest, having run only in the afternoon, while Stoffel Vandoorne finally gave McLaren something to smile about with the fourth fastest time with a late lap in the closing minutes of the session.

Despite no changes having been made to the engine specification since Tuesday's troubles, McLaren endured a pretty much trouble-free day of testing as Honda encountered no repeat of the MGU-H problems that have dogged it for the past week.

In fact, McLaren racing director Eric Boullier called it the "best day" of testing that the team had enjoyed so far this year

With a late short run, Vandoorne was able to set a lap of 1m32.108 seconds – just eight tenths off Bottas's best lap of the day. More encouragingly, though, was that Vandoorne completed 81 laps – more than a race distance.

Kevin Magnussen continued work on Haas' evaluation of brakes to set the fifth fastest time, while Esteban Ocon's morning time in the Force India was good enough to leave him sixth overall at the end, ahead of Toro Rosso's Daniil Kvyat and Williams driver Gary Paffett.

Renault's Sergey Sirotkin finished his first day of testing with the French car manufacturer ahead of Red Bull's Pierre Gasly and Sauber's Pascal Wehrlein.