Nico Rosberg has held on to top spot on the opening day of the second pre-season test after sprinting clear of his rivals on soft tyres as Mercedes begins to demonstrate its true pace.
With Mercedes opting to split its driver time between Nico Rosberg and Lewis Hamilton to a session per day, the German completed a race simulation before strapping on the yellow-banded soft Pirelli tyres and set an impressive 1m 23.022s.
The time remained undefeated through the entire afternoon session and is the second quickest time in combined pre-season testing – only two-tenths off of Sebastian Vettel's best time on the purple ultra-soft compounds.
Valtteri Bottas took a run at the fastest time with the new ultra-soft tyres but trailed by 0.207s, which could be a small indication of the Mercedes advantage, albeit without knowing the fuel loads of each timed lap.
Elsewhere, new team Haas endured a tricky afternoon after suffering a fuel system problem which ruled Esteban Gutierrez out of any further track time after lunch. The Mexican had only been able to notch up 23 laps to his name with a best time of 1m 26.661s which put him second bottom.
Despite not making progress on the timescreens, Rio Haryanto at least got some valuable track time in the Manor after effectively missing the entire morning session with an oil leak. There was a final red flag stoppage caused by Kevin Magnussen in the Renault as he came to a halt on track with less than 10 minutes remaining.
Fernando Alonso enjoyed a remarkable turnaround in fortunes having effectively missed the whole of the final day of the first test as the McLaren-Honda produced a healthy bank of 93 laps and ended the day third fastest despite a small scare after stopping at the exit of pitlane in the final minutes of the morning.
Kimi Raikkonen suffered a similar stop at the pitlane exit an hour into the afternoon but Ferrari quickly resolved its problems to notch up 72 laps.
Lewis Hamilton ended the day sixth overall, just behind a low-key Daniil Kvyat, after the Mercedes driver opted not to strap on the softer tyres.
Max Verstappen produced a mega haul of laps, 144, to give Toro Rosso's new 2016 livery plenty of exposure in a trouble-free day.
With Nico Hulkenberg having another solid day in the VJM09 for Force India, Felipe Nasr debuted the Sauber C35 by logging 103 laps on day one as Magnussen, Gutierrez and Haryanto completed the timesheet after suffering their respective technical issues.