Suzuka, Japan: Sebastian Vettel crashed while Jenson Button, the only man standing between the Red Bull driver and a second Formula One title, was quickest in both Japanese Grand Prix practice sessions yesterday.

Vettel, who needs only a point tomorrow to be the sport's youngest double champion at the age of 24, made a rare error on the exit to the Degner 1 curve at the end of a warm morning practice at Suzuka. He skimmed across the gravel and ended the 90-minute session as a sweaty spectator, removing his helmet and joining marshals behind the crash barriers with his car's nose in the tyre wall.

"It wasn't a big mistake this morning, but in that moment I wasn't 100 per cent awake and mistakes around here can be quite costly," said the German, who was third fastest in both sessions.

Vettel looks sure to retain his title with four races to spare and has won from pole at Suzuka for the past two years. The reigning champion has a 124-point lead over Button.

Button must win on Sunday and hope Vettel fails to score for the first time in 17 races dating back to last October. The Briton lapped the track with a fastest time of one minute 31.901 seconds in the afternoon. His quickest time in the morning was 1:33.634.

Button fastest while Vettel crashes

First free practice

1. Jenson Button (GBR) McLaren 1:33.634, 2. Lewis Hamilton (GBR) McLaren 1:33.725, 3. Sebastian Vettel (GER) Red Bull 1:34.090, 4. Fernando Alonso (ESP) Ferrari 1:34.372, 5. Mark Webber (AUS) Red Bull 1:34.426, 6. Jaime Alguersuari (ESP) Toro Rosso 1:34.937, 7. Felipe Massa (BRA) Ferrari 1:35.585, 8. Sebastien Buemi (SWI) Toro Rosso 1:35.590, 9. Michael Schumacher (GER) Mercedes 1:36.033, 10. Vitaly Petrov (RUS) Lotus-Renault 1:36.370.

Second free practice

1. Jenson Button (GBR) McLaren 1:31.901, 2. Fernando Alonso (ESP) Ferrari 1:32.075, 3. Sebastian Vettel (GER) Red Bull 1:32.095, 4. Mark Webber (AUS) Red Bull 1:32.147, 5. Felipe Massa (BRA) Ferrari 1:32.448, 6. Michael Schumacher (GER) Mercedes GP 1:32.710, 7. Nico Rosberg (GER) Mercedes GP 1:32.982, 8. Lewis Hamilton (GBR) McLaren 1:33.245, 9. Vitaly Petrov (RUS) Lotus-Renault 1:33.446, 10. Sebastien Buemi (SWI) Toro Rosso 1:33.681.