Sebastian Vettel kept Ferrari on top of the times on the second day of pre-season testing at the Barcelona circuit on Tuesday.
The Ferrari driver took advantage of a run on the new ultra-soft tyres in the morning session to set a best time of 1:22.802, nearly two seconds quicker than the pole position time for last year's Spanish Grand Prix, which had been set by Nico Rosberg on the medium compound.
It was a highly productive day for Vettel as well, the German covering 126 laps on his way to the best time of the day.
He caused a red flag at the end of the day, however, his car stopping at Turn 3 with five minutes left on the clock.
The four-time champion emerged on top after outpacing Daniel Ricciardo in the Red Bull, the latter also using ultra-softs to set his fastest time - and logging 112 laps.
Force India's Sergio Perez, taking over from Alfonso Celis, was third fastest ahead of Rosberg, who replaced Lewis Hamilton on board the new Mercedes W07.
Perez set his time on super-soft tyres, while Rosberg was the quickest man on mediums.
The German car proved to be ultra-reliable once more and Rosberg's 172 laps took Mercedes' overall tally to well over 300 over the course of the two days of testing.
Marcus Ericsson completed the top-five in the 2015 Sauber, ahead of the Williams of Valtteri Bottas.
The Haas team enjoyed a promising day of work as Esteban Gutierrez took over from teammate Romain Grosjean in the Ferrari-powered car.
Gutierrez finished in seventh, some three seconds off the pace using soft tyres, and covered 79 laps.
Pascal Wehrlein completed a full day of work for Manor as the team decided to alter its scheduled plan of running Rio Haryanto. The German driver wound up eighth.
Fernando Alonso made his debut at the wheel of the new McLaren MP4-31, replacing Jenson Button in the Honda-powered car.
The Spanish driver had a solid day of work and managed over 119 laps, but finished down in ninth position over three seconds off the pace, his best time set with soft tyres.
The Renault team had another troubled day after managing just 37 laps on Monday.
Jolyon Palmer's session came to an early finish today after an apparent engine problem, with smoke pouring out of his car right as he left the pits some 45 minutes after the lunch break. He did not return to the track after that.
The Briton will be replaced in the car tomorrow by teammate Kevin Magnussen.
Toro Rosso's Max Verstappen finished at the bottom of the times on his first day at the wheel of the new car, despite logging 120 laps.
The Dutchman caused the first red flag of the day when his car ground to a halt in the morning.
Barcelona test times, Day 2:
|2||D. Ricciardo||Red Bull||1:23.525||112|
|3||S. Pérez||Force India||1:23.650||101|
|11||M. Verstappen||Toro Rosso||1:26.539||121|