Lewis Hamilton led the way for the first practice session in Sepang, finishing half a second ahead of Sebastian Vettel. The pair of them battled for the top spot through the session, but it was the Brit who claimed the top spot. Narain Karthikeyan, in the HRT, had a difficult start to the weekend with gearbox issues that brought him to a halt out on track. He still managed to finish the session ahead of his teammate, however. Back towards the top, the Mercedes duo finished just a thousandth of a second apart from each other, finishing third and fourth. Romain Grosjean also continued his strong start to the year, with fifth place. Valterri Bottas was in for Bruno Senna in the Williams, and he finished the day 11th.