World champion Sebastian Vettel posted the fastest time during pre-season testing in Barcelona on Tuesday.
The German, 24, clocked a day-best time of 1 minute, 23.265 seconds in Spain to be easily quickest in his Red Bull.
Force India's Nico Hulkenberg was 0.175 seconds slower in second, while McLaren driver Lewis Hamilton completed 114 laps and was third on the timesheets.
Frenchman Charles Pic, of Marussia, finished with the most laps after going around Circuit de Catalunya 121 times.
Vettel, who has won consecutive drivers' championships, surpassed Hulkenberg's time in the first session before bettering his own effort later in the day.
Australian Toro Rosso driver Daniel Ricciardo was fourth, ahead of Ferrari's Fernando Alonso, who spent a large part of the first session in the garage.
Michael Schumacher, in his 2012 Mercedes after the introduction of the car had been delayed by a fortnight, was ahead of Sauber's Sergio Perez and the Williams of Bruno Senna.
Caterham's Heikki Kovalainen and Lotus' Romain Grosjean rounded out the top 10 despite issues during the second pre-season test.
Lotus had several problems, with Frenchman Grosjean completing just seven laps before the team decided to send their chassis back to their base at Enstone for checks.
Caterham also had troubles after Kovalainen stopped on the circuit having finished nine laps, but the Finn returned later in the day.
There were two red flags - once for Kovalainen and the other when Ricciardo came to a stop.