Kimi Raikkonen hit the front of the Barcelona timesheets on Thursday morning as he set the fastest lap time of the pre-season on Pirelli's ultra-softs.
The Ferrari driver, who replaced team-mate Sebastian Vettel for the penultimate day's running, caused a stir in the morning as he ventured out in an SF16-H fitted with a halo cockpit protection device. That was removed after his installation lap and Raikkonen began work on the day's programme.
Swapping to the soft tyres the Finn went fastest with a 1:23.009 but a change over to the ultras saw him shave tenths off his time. He posted a 1:22.765 in the hour before lunch, replacing Vettel's 1:22:810 as the best time of the pre-season.
Nico Hulkenberg was second quickest on Thursday, 0.466s off Raikkonen's pace, while Max Verstappen was further, a further 0.131s down. Both drivers set their times on the ultra-softs.
Nico Rosberg was fourth with his 1:24.126 that fastest of the medium tyre runners while Felipe Nasr was next in line ahead of Fernando Alonso and Daniil Kvyat.
Felipe Massa and Jolyon Palmer both stayed on the medium tyres, finishing eighth and ninth, ahead of Romain Grosjean. It was a vastly improved day for Haas, who resolved their turbo issues to cover 59 laps. However, it ended a minute before the lunch break with Grosjean off the track and in the gravel at Turn 4.
Pascal Wehrlein completed the timesheets in 11th place with a 1:28.476.
1 Raikkonen Ferrari 1:22.785 41 laps
2 Hulkenberg Force India 1:23.251 49 laps
3 Verstappen Toro Rosso 1:23.382 59 laps
4 Rosberg Mercedes 1:24.126 81 laps
5 Nasr Sauber 1:24.768 37 laps
6 Alonso McLaren 1:24.870 57 laps
7 Kvyat Red Bull 1:25.141 62 laps
8 Massa Williams 1:25.420 46 laps
9 Palmer Renault 1:27.182 26 laps
10 Grosjean Haas 1:28.110 59 laps
11 Wehrlein Manor 1:28.476 19 laps