Lewis Hamilton set the fastest time of the first morning of the final pre-season test as Mercedes once again showed impressive pace.
Following Nico Rosberg's medium tyre lap which caught the eye at the end of the second test, Hamilton went comfortably clear early on the opening day with a time of 1:24.881 on the medium tyre. Hamilton's time was a tenth quicker than his best from the second test on the same tyre.
Felipe Massa was second quickest for Williams on a cool and overcast morning, posting a best time of 1:25.763 in the FW37. That left him just 0.16s clear of Daniil Kvyat's Red Bull, with the Russian the only other drive to dip below the 1m27s mark.
Kvyat also set the only brief red flag period of the morning as he stopped at the pit lane exit when attempting to head out for an installation lap. However, proceedings were later halted by light rain which saw limited running in the final hour of the session.
McLaren's dismal pre-season continued as Jenson Button was only able to complete seven laps due to a power unit issue, leaving him still short of 100 in total across the three tests. Button is set to do the majority of running with Fernando Alonso ruled out following his crash on Sunday, with Kevin Magnussen also scheduled to run at some stage.
While well behind on its pre-season testing plan, Thursday morning was not a day for significant mileage for any team as none of the eight runners surpassed 50 laps.
Outside the top three, Romain Grosjean completed 33 laps and set the fourth fastest time but was some two seconds slower than Hamilton's best. Marcus Ericsson was fifth after testing a number of aerodynamic updates on the Sauber, while Kimi Raikkonen completed just 28 laps en-route to the sixth quickest time.
Toro Rosso unveiled an upgraded STR10 with a shortened nose on Thursday morning, with technical director James Key admitting it was a "radical difference" from the car which was launched at Jerez. Carlos Sainz Jr was second slowest ahead of Button as Toro Rosso focused on aero runs to analyse the new parts.
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Driver line-ups for the final test
Click here for the gallery from day one of the final test
