Nico Rosberg led a Mercedes one-two in the first practice session for the Chinese Grand Prix as he set about attempting to follow up on his victory 12 months ago at the same circuit.
Team-mate Lewis Hamilton was second fastest and 0.454s off Rosberg as Mercedes comes to this weekend with new front and rear wings, new brake ducts and a new cooling system. The early signs are good with the nearest competitor, Red Bull's Mark Webber, 0.941s off the pace of Rosberg. However, the teams only ran the harder medium compound tyre during FP1, with the soft compound set to make an appearance in the afternoon.
Webber was just under 0.3s clear of his team-mate Sebastian Vettel as the Red Bull pair returned to the track for the first time since their bitter battle in Malaysia. That gap is likely to remain close throughout the weekend but it won't be until the race that we see the two cars fighting wheel-to-wheel on track.
Fernando Alonso ended up fifth, just off the pace of Vettel, while Jenson Button showed signs of promise at McLaren with the sixth fastest time. However, Sergio Perez gave the McLaren mechanics a little extra work at the end of the session after sticking the nose of his car in the wall on his return to the pits. He appeared to be pushing the limits on his final in-lap but in doing so locked up on entry to the pits, ran through the gravel where Lewis Hamilton beached his car in the 2007 race and decimated his front wing against the tyre barrier. His best time wasn't any more encouraging as he ended the session 16th and 2.643s off the pace.
Both Force Indias featured in the top ten with Adrian Sutil eighth and Paul di Resta 10th as the team again looks competitive this weekend. Romain Grosjean's Lotus split the two in the times with his team-mate Kimi Raikkonen 11th fastest. Raikkonen appeared to be struggling slightly after spinning early in the session and only completed 16 laps by the end of the morning.
Jean-Eric Vergne was 12th fastest in the Toro Rosso ahead of a tight battle with the Williamses and Saubers over what will become the battle for Q2 positions in qualifying. Among the backmarkers it was once again Jules Bianchi and Marussia that led the way, but they were still nearly two seconds off the Sauber of Esteban Gutierrez in 18th. Caterham rounded off order with Giedo van der Garde ahead of reserve driver Ma Qing Hua, who made his FP1 debut for the team in Charles Pic's car and was 1.5s off van der Garde. Pic will be back in the No.20 Caterham for the rest of the weekend.