Spanish Grand Prix winner Nico Rosberg dominated the timesheet on the opening day of testing at the Barcelona circuit on Tuesday.
The Mercedes driver, fresh from his first victory of the season on Sunday, completed a marathon session at the wheel of the German car, finishing with a best time of 1:24.374, over two seconds clear of his closest rival.
His lap was quicker than Saturday's pole position time.
On top of his pace, Rosberg also had an extremely productive session, covering a total of 146 laps, over two grand prix distances.
Sauber's Marcus Ericsson finished in second place after nearly 100 laps.
Raffaele Marciello, who will replace Ericsson at Sauber tomorrow, drove for Ferrari today, managing 125 laps on his way to the third fastest time of the session.
Red Bull's Daniil Kvyat and Pastor Maldonado in the Lotus completed the top five.
Briton Nick Yelloly, not scheduled to drive until tomorrow, was in charge of testing duties for Force India after Pascal Wehrlein was unwell to drive.
Yelloly also had a busy day, covering 109 laps on his way to the sixth fastest time.
Pierre Gasly, another man who will switch teams tomorrow, was at the wheel of the Toro Rosso, finishing seventh ahead of the Williams of Felipe Massa.
McLaren finished at the bottom of the times with Oliver Turvey, the Briton ending the day with 66 laps.
|4.||Daniil Kvyat||Red Bull-Renault||1:26.904||+2.530||100|
|6.||Nick Yelloly||Force India-Mercedes||1:27.396||+3.022||109|
|7.||Pierre Gasly||Toro Rosso-Renault||1:27.639||+3.265||128|