Red Bull's Mark Webber set the pace in opening practice for the Malaysian GP

Red Bull's Mark Webber set the pace in opening practice for the Malaysian Grand Prix ahead of Kimi Raikkonen and Sebastian Vettel.

The Australian lapped the 5.543km track in a time of 1:36.935 seconds, a time just 0.068s faster than Raikkonen, who won Webber's home race last weekend.

Vettel was 0.169s behind his team-mate in a session which brought evidence that tyre wear looks set to remain top of the F1 agenda.

After the usual slow start, most drivers completed two runs using a set of Pirelli's hard compound tyre, which has been nominated along with the medium this weekend. All the fastest times were set on the first run, with cars lapping a good three seconds slower towards the end of the session.

Fernando Alonso was fourth fastest for Ferrari ahead of Mercedes' Nico Rosberg. Respective team-mates Felipe Massa and Lewis Hamilton were seventh and ninth, with the top ten completed by Adrian Sutil and Paul di Resta (both Force India) and Romain Grosjean (Lotus).

With the teams' 2013 cars running on Pirelli's new range of tyres in hot conditions for the first time, it came as little surprise to hear the feedback drivers eventually gave.

Hamilton reported towards the end of the session that "my rear tyres are destroyed" while Caterham rookie Giedo van der Garde said that all drivers were struggling with their left front, which is placed under particular strain through corners like the fast left-right of Turns 5 and 6.

As usual, the session started slowly with teams performing a balancing act. On the one hand, they had to evaluate set-ups, test new parts and - in the case of McLaren and Williams at least - try and look for answers. On the other, they needed to make their tyres last.

More cars took to the track after half an hour, with McLaren a conspicuous presence. Having had a troubled start to the season, Jenson Button (11th) and Sergio Perez (13th) concentrated on the ride-height problems that saw their cars bottoming out in Melbourne.

With Red Bull running one-two after an hour, Raikkonen was still sitting in his garage after his Lotus developed a KERS problem. It was soon fixed, however and, taking to the track, he moved ahead of Vettel almost immediately.

Much like everyone else, though, that was as good as it got for Raikkonen. Tell-tale marking soon appeared on tyres, with graining and perhaps even blistering looking set to be a problem this weekend.

Elsewhere, Williams drivers Pastor Maldonado and Valtteri Bottas were 12th and 16th as the team's attempts to find the right development direction saw them again running different specifications of car.

Max Chilton, meanwhile, was the first driver to put a lap on the board but the Marussia rookie ended the session slowest, 4.578s down on Webber.