The reigning world champion reported loss of power, and although he was confident he could have made it back to the pits, Mercedes, concerned that he was running a race engine, instructed him to stop on track. The car was subsequently recovered to the pits where Mercedes diagnosed an engine problem.
In the end, Ferrari’s Kimi Raikkonen provided Rosberg’s fiercest opposition, lapping in 1m 40.497s right at the end of the session to go second, just 0.373s adrift of the German. The Finn’s team mate Sebastian Vettel also improved right at the end, recording a lap of 1m 40.985s for third. It was interesting, however, that while Rosberg had long switched to some race running, the Ferraris were still pursuing outright speed.
Romain Grosjean gave Lotus a big boost with a solid fourth fastest time on 1m 41.543s, which just edged out the once again impressive Carlos Sainz Junior, who showed that there isn’t too much wrong with Renault’s power unit as he lapped in 1m 41.596s for Toro Rosso. That once more outpaced Daniel Ricciardo’s Red Bull, which the Australian took round in 1m 41.787s to head Max Verstappen in the other STR10 on 1m 41.803s.
Williams had a tough morning, with the FW37s looking wayward as Valtteri Bottas set the eighth fastest time in 1m 41.882s and Felipe Massa the 11th on 1m 42.103s, or else were pursuing their usual policy of race-tuning the cars rather than seeking fast times in the first session. What’s for sure is that they didn’t look as comfortable out on the track as the Ferraris, and to make matters worse the team were subsequently penalised by the stewards for Massa using his first set of hard tyres for marginally longer than allowed.
Between the two Williams pilots, Daniil Kvyat lapped his Red Bull in 1m 42.055s for ninth before complaining of issues with the brakes and power loss, as Marcus Ericsson spearheaded the Sauber challenge in 10th on 1m 42.064s.
Pastor Maldonado was one of many to have off-track moments as the surface slowly rubbered-in, and was 12th in the second Lotus on 1m 42.567s, as rookie Raffaele Marciello recorded 1m 42.621s for 13th in a solid Friday morning session debut for Sauber. That left the Italian ahead of returnee Fernando Alonso on 1m 42.885s for McLaren. As Jenson Button had suggested, the other silver cars were closer to the pace here, but both the Spaniard and the Englishman, an unhappy 17th on 1m 43.100s, were all over the place whenever they tried to push the MP4-30 too hard.
Force India were still paying the price for their lack of pre-season testing with the VJM08; Nico Hulkenberg was 15th on 1m 42.893s and Sergio Perez went off several times trying to better 1m 43.054s which left him just ahead of Button in 16th.
There was cheer when Will Stevens and Roberto Merhi followed Marcus Ericsson out on to the track at the start of the session, as Marussia finally turned in their first laps of the 2015 season. Stevens was within 107% of Rosberg’s time with his best lap of 1m 46.686s, but Merhi finished just outside it on 1m 47.683s after mechanical problems kept him in the garage for much of the session.
As expected, everyone ran exclusively on Pirelli’s hard tyre.