Lewis Hamilton has admitted he took the Formula One world championship too lightly last year.

Hamilton is back in Japan, where he won last year to open a 12-point lead in the championship with two races left in his debut season.

But he squandered that advantage in China and Brazil and finished one point behind the championship winner Kimi Raikkonen.

Hamilton said: "I was leading here but I didn't really understand the magnitude of the situation I was in and what was around me and the pressure that was on my shoulders. I dealt with it the best I could, but it wasn't the best.

"But I learnt from those mistakes and I have come this year and I've taken a big step in my life as a grown-up, while as a driver I have matured and and worked as hard as I can to improve in all areas.

"I didn't really focus on the championship last year whereas this year I have as well as the importance of finishing races."

Hamilton recorded the fastest time in the first free practice session at the Fuji Speedway circuit and Tim Glock was fastest in the second session in his Toyota, while Hamilton was third fastest.