Sebastian Vettel's dominant run continued as Red Bull's world champion set the pace in practice for the Chinese Grand Prix.
McLaren were again his closest rivals as Lewis Hamilton was 0.166 seconds behind with team-mate Jenson Button third ahead of both Mercedes drivers.
Ferrari's Fernando Alonso was 14th in second practice following a problem with the hydraulics on his car.
Scot Paul di Resta missed the second session with a fuel-pressure problem.
It was a frustrating day for Renault's Nick Heidfeld, who crashed twice.
The Formula 1 field had returned to action just five days after 16 of the 24 cars crossed the line in Malaysia.