Mercedes resumed business as usual during the first practice session of the Chinese Grand Prix as Lewis Hamilton led team-mate Nico Rosberg at the top of the timesheets.
Malaysian Grand Prix race-winner Sebastian Vettel returned to reality with a gap of over a second to Hamilton despite a late attempt to improve on his final run. The deficit at this stage of the weekend is unlikely to be a true indicator of form, but it appears the cooler temperatures and different car characteristics required at the Shanghai International Circuit may suit Mercedes over Ferrari. Mercedes spent much of its morning analysing new front wing designs, aimed at getting its drivers back ahead of Vettel this weekend, but team boss Toto Wolff was still wary of a long run performed by Ferrari driver Kimi Raikkonen at the end of the session.
Raikkonen's fastest single lap was a further 0.5s off Vettel's best, but he did not chase a late quick lap in the closing minutes of the session like his Ferrari team-mate. With track conditions improving with every lap, FP2 will be a better indicator of the relative performances of the two Ferrari drivers as they also get a chance to sample the soft tyres.
There was a tight battle outside the top four with the two Red Bulls and Carlos Sainz's Toro Rosso within a tenth of fifth-placed Felipe Nasr in the Sauber. Valtteri Bottas and Felipe Massa rounded out the top ten, although it's rare for Williams to show its true hand until later in the weekend.
Jenson Button showed the early signs of further improvements for McLaren with the 13th fastest lap and a time that was within a second of Nasr in fifth. Fernando Alonso finished the session 17th and gained another 20 laps of experience behind the wheel of the Honda-powered MP4-30.
Jolyon Palmer made his race weekend debut for Lotus, standing in for Romain Grosjean who will return to the cockpit from FP2 onwards. Palmer made a mistake on his first set of tyres, but he was not alone in running off track over the 90 minutes with the tricky braking zones at Turn 1 and Turn 14 catching out rookies and world champions alike.