Nico Rosberg fired the first shots at opening practice for the British Grand Prix by snatching the fastest time from teammate Lewis Hamilton.
A hydraulic failure in Rosberg car early in the session confined him to setting just 12 timed laps, but his best — a 1 minute 34.344 seconds — was enough to keep the home favourite at bay by a margin of just 0.070 seconds.
Mercedes, however, ended the session under investigation after technical delegate Jo Bauer recommended the team to the stewards for covering Rosberg’s car after it stopped on track, allegedly contrary to sporting regulation 27.4.
It was Max Verstappen who impressed most, however, with a time good enough for third in the session, albeit 1.256 seconds adrift of the leaders.
Verstappen has made a name for himself mixing in with the frontrunners on Friday, which is testament to a Toro Rosso chassis he described as the second best in the field.
“When I compare high-speed performance, if we had the [Mercedes] engine, I think we would be P2,” he said on Thursday.
Teammate Carlos Sainz, though marginally less effusive in his description of the car, was just over a tenth slower than his teammate, finishing fifth fastest.
The pair were separated by Kimi Räikkönen’s Ferrari with a half-tenth buffer on either end.
The second Ferrari, piloted by Sebastian Vettel, finished sixth quickest and a further tenth behind, ahead of the Red Bull Racing duo headed by Daniel Ricciardo.
Nico Hülkenberg headlined an underwhelming debut of Force India’s B-spec 2015 car, managing to lap all of 1.883 seconds off Rosberg’s pace and three tenths off Red Bull’s quickest time, the four-time championship winner being the Indian squad’s new constructors championship target.
Felipe Massa was the lead Williams driver and the first beyond the two-second buffer, as is usual for Williams on Friday, ahead of Felipe Nar’s Sauber and the second Force India of Sergio Perez.
Susie Wolff and Jolyon Palmer, both British drivers testing for Williams and Lotus respectively in FP1, finished side by side in thirteenth and fourteenth, separated by just two hundredths of a seconds, with just a tenth separating them from fellow reserve tester Raffaele Marciello in the second Sauber.
Pastor Maldonado completed just eight laps to take the sixteenth-quickest time.
Fernando Alonso and Jenson Button both ran with limited sessions owing to the team’s desire to minimise mileage on two old engines. Alonso finished 3.948 seconds off the pace with Button almost seven tenths further back.
Will Stevens and Roberto Merhi remained anchored to the bottom of the grid despite a new colourful livery and significant aerodynamic upgrades, though Merhi’s slowest time was four-tenths quicker than the 107 per cent cut-off time.