Nico Rosberg led a Mercedes one-two in the opening practice session for the Spanish Grand Prix at Barcelona.
The German driver set a best time of 1:26.818 in the updated Mercedes to finish less than a tenth of a second ahead of teammate Lewis Hamilton.
Mercedes dominated the session, with Ferrari's Sebastian Vettel finishing in third, but nearly a full second behind Rosberg.
Vettel's teammate Kimi Raikkonen was fourth quickest ahead of local hero Carlos Sainz, who started his home race in promising fashion for Toro Rosso. Teammate Max Verstappen finished right behind in sixth.
Red Bull's Daniil Kvyat trialled the team's new short nose, finally introduced after some failed attempts in the crash tests, and went seventh fastest, ahead of Felipe Massa in the Williams.
Kvyat's teammate Daniel Ricciardo, already using his fourth Renault engine, reported power unit problems right at the start of the session and had to spend a lot of time in the pits while his mechanics worked on the problem.
The Australian did not return to the track until there were just eight minutes left on the clock and managed just nine laps on his way to the ninth fastest time.
Felipe Nasr completed the top 10 in the Sauber.
The McLaren of Fernando Alonso and Jenson Button finished down in 15th and 16th respectively, the Spaniard finishing his session with a spin.
Sauber's Raffaele Marciello was quickest of the three Friday drivers in action today, the Italian finishing 12th ahead of the Lotus of Jolyon Palmer and Susie Wolff in the Williams.
|05||C. Sainz||Toro Rosso||1:28.132||+1.304||27|
|06||M. Verstappen||Toro Rosso||1:28.529||+1.701||23|
|07||D. Kvyat||Red Bull||1:28.785||+1.957||7|
|09||D. Ricciardo||Red Bull||1:29.075||+2.247||9|
|11||N. Hulkenberg||Force India||1:29.409||+2.581||20|
|17||S. Perez||Force India||1:30.096||+3.268||19|