The Mercedes pair of Nico Rosberg and Lewis Hamilton occupied their familiar positions atop the timesheet following the first free practice session ahead of the Spanish Grand Prix.
Hamilton said on Thursday the team were bringing a small number of quality upgrades to Barcelona and, although it was team-mate Rosberg who clocked the fastest time, the duo still had the beating of the rest of the field.
Rosberg set a time of one minute 26.828 seconds to beat Hamilton by less than a tenth of a second, while the Ferraris again proved to be their closest challengers.
Sebastian Vettel was almost a second off the pace in third with team-mate Kimi Raikkonen a place further back, with Spaniard Carlos Sainz impressing in his first home grand prix by putting his Toro Rosso fifth.
Max Verstappen followed team-mate Sainz in sixth while Daniil Kvyat’s Red Bull was seventh with Felipe Massa eighth for Williams. Susie Wolff in the sister car was 14th fastest as she replaced Valtteri Bottas for the session.
Raffaele Marciello and Jolyon Palmer were also stepping in for first practice and were 12th and 13th for Sauber and Lotus, respectively.
Felipe Nasr remained at the wheel of his Sauber and, along with the second Red Bull of Daniel Ricciardo, rounded out the top 10 with Force India’s Nico Hulkenberg 11th.
Fernando Alonso, who suffered a concussion following a testing accident at the Circuit de Catalunya in February, was the quickest of the two McLarens, although both he and Button were almost three seconds adrift of Rosberg’s time.
Sergio Perez was 17th for Force India and Pastor Maldonado could only manage seven laps for Lotus, finishing 18th and ahead of the Manor pair of Will Stevens and Roberto Mehri.