Mercedes' Nico Rosberg and Lewis Hamilton topped the times in first practice in China

Mercedes' Nico Rosberg topped the times ahead of Lewis Hamilton in opening practice for the Chinese Grand Prix on Friday.

Mercedes ran a new front wing during the session and weren't alone in trialling upgrades, with Ferrari also running a new front wing while McLaren tried out a new floor. Sauber have a new rear wing and floor developments, with Force India changing the floor of di Resta's car during the session. And while Sky Sports F1's Ted Kravitz initially spotted nothing particularly new on Red Bull's RB9 - he did, however, see boxes arriving at the back of their garage, suggesting changes for P2 - Rachel Brookes reported a full house on Williams' car. As the team look to overcome their poor start to the season, Pastor Maldonado (13th) and Valtteri Bottas (17th) took to the track in FW35s sporting new front wings, rear wings and new floors. With Button setting the session's first timed lap (1:41.798s) half an hour in, Force India were also prominent early on. Sutil (1:38.125s) was fastest after 50 minutes, by which time all the runners were undertaking their preliminary runs. Massa and Rosberg both took turns at the top, with the latter then setting the time that was to prove the benchmark. As ever, tyre degradation is bound to figure this weekend. Pirelli have nominated their medium and soft rubber and with cars running in warm, sunny conditions, graining was noticeable on some front tyres. Red Bull, for one, reported wear and Friday's afternoon session will give more pointers as to whether problems similar to those they experienced in both Australia and Malaysia - which precipitated the team orders row there - might happen once again. Elsewhere, Kimi Raikkonen was 11th after suffering a spin while Sergio Perez wound up 16th and also, embarrassingly, in the gravel after the chequered flag fell. Entering the pitlane too quickly, the Mexican locked up and ploughed to a halt in the gravel trap his predecessor Hamilton made famous during the 2007 race.