Lewis Hamilton says he is surprised by how strong Ferrari looks following practice for the Malaysian Grand Prix.

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While Hamilton himself topped the times in the second practice session, Kimi Raikkonen was second quickest ahead of Nico Rosberg in the other Mercedes. On Thursday, Hamilton praised Ferrari for the glimpses of pace it showed in Australia, but admits he didn't expect such close competition at Sepang.

"Ferrari look great!" Hamilton said. "It’s surprising to see how good their times are. We will see whether that continues throughout the weekend."

Hamilton's day was compromised by a power unit inlet system problem which caused him to stop on track during FP1. With Mercedes managing to repair the issue in time to allow him to return to the track during the second session, Hamilton says it could prove important to his chances of victory this weekend.

"Firstly it was an amazing job done by my guys to rebuild the car, get the engine back on and gearbox and get back out, I am very grateful for that. Especially here where it is so hot and so difficult for the tyres, so it was really important get back out.

"It affects you quite a bit. Fortunately I got a few laps with a longer run in the end, but in terms of my set-up, I have not made any changes and it is quite a bit off from where we need it.

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