SUZUKA, Japan - Red Bull's Sebastian Vettel limbered up for the 2013 Japanese Grand Prix that could bring him a fourth successive Formula 1 title as he set the fastest time during the second practice session.Vettel, who could wrap-up the 2013 Championship if he wins on October 13 and Ferrari's Fernando Alonso fails to finish in the top eight, lapped with a best time of 1min33.852.Alonso, 77 points behind Vettel with five races remaining, ended the day in sixth and 10th during the first and second sessions respectively.CRASHES IN SUZUKAWhile Vettel steered clear of trouble, Lotus' Kimi Raikkonen, Williams' Pastor Maldonado and McLaren's Sergio Perez all went off the track during the second session.Perez's crash was the hardest, with the McLaren rookie slamming into the barriers. Raikkonen went into the gravel half an hour from the end of practice but managed to finish fourth. Marussia's Jules Bianchi and Caterham's Giedo van der Garde ended up in the tyre wall during the first session. Bianchi did not take part in the second session as mechanics were still rebuilding his car. First practice saw Lewis Hamilton lead a Mercedes one-two with team mate Nico Rosberg in a session with four teams filling the top eight places in pairs. The Mercedes pair were followed by the two Red Bulls (Vettel, Mark Webber), Ferrari (Felipe Massa, Alonso) and Lotus (Romain Grosjean, Raikkonen).Hamilton's best time of 1min34.157 was set on hard tyres. FOURTH TITLE IN THE BAG?Vettel, who is chasing his fifth win in a row, was 0.611 seconds off Hamilton's pace in first session. Team mate Webber, using a new chassis after retiring at the 2013 Korean Grand Prix with his Red Bull in flames, was second fastest with a time of 1min34.020.Vettel has won three of the last four races at Suzuka, a favourite track where he won the 2011 title and can count on the support of a large contingent of fans.Ferrari's Massa, runner-up at Suzuka in 2012, was faster than Alonso in both sessions. Daniel Ricciardo, who replaces Webber at Red Bull in 2014, was in the top ten throughout the day for Toro Rosso.2013 Japanese Grand Prix at Suzuka results:Second practice:1 Sebastian Vettel (Germany) Red Bull 1min33.852 2 Mark Webber (Australia) Red Bull 1min34.020 3 Nico Rosberg (Germany) Mercedes 1min34.114 4 Kimi Raikkonen (Finland) Lotus 1min34.202 5 Romain Grosjean (France) Lotus 1min34.411 6 Lewis Hamilton (Britain) Mercedes 1min34.442 7 Daniel Ricciardo (Australia) Toro Rosso 1min34.473 8 Felipe Massa (Brazil) Ferrari 1min34.698 9 Jenson Button (Britain) McLaren 1min34.912 10 Fernando Alonso (Spain) Ferrari 1min35.087 11 Esteban Gutierrez (Mexico) Sauber 1min35.089 12 Jean-Eric Vergne (France) Toro Rosso 1min35.109 13 Nico Huelkenberg (Germany) Sauber 1min35.182 14 Paul Di Resta (Britain) Force India 1min35.275 15 Adrian Sutil (Germany) Force India 1min35.341 16 Sergio Perez (Mexico) McLaren 1min35.709 17 Valtteri Bottas (Finland) Williams 1min36.136 18 Pastor Maldonado (Venezuela) Williams 1min36.722 19 Charles Pic (France) Caterham 1min37.630 20 Giedo van der Garde (Netherlands) Caterham 1min37.905 21 Max Chilton (Britain) Marussia 1min38.121 22 Jules Bianchi (France) Marussia No TimeFirst practice1 Lewis Hamilton (GBR) Mercedes 1min34.1572 Nico Rosberg (GER) Mercedes 1min34.4873 Sebastian Vettel (GER) Red Bull Racing 1min34.7684 Mark Webber (AUS) Red Bull Racing 1min34.7875 Felipe Massa (BRA) Ferrari 1min35.1266 Fernando Alonso (ESP) Ferrari 1min35.1547 Romain Grosjean (FRA) Lotus 1min35.1798 Kimi Raikkonen (FIN) Lotus 1min35.3649 Sergio Perez (MEX) McLaren Mercedes 1min35.45010 Daniel Ricciardo (AUS) Toro Rosso 1min35.635 11 Jenson Button (GBR) McLaren Mercedes 1min35.86812 Nico Hulkenberg (GER) Sauber 1min35.90013 Jean-Eric Vergne (FRA) Toro Rosso 1min36.066 14 Adrian Sutil (GER) Force India 1min36.16515 Pastor Maldonado (VEN) Williams 1min36.17816 Valtteri Bottas (FIN) Williams 1min36.34017 Paul di Resta (GBR) Force India 1min36.39918 Esteban Gutierrez (MEX) Sauber 1min36.76019 Heikki Kovalainen (FIN) Caterham 1min37.59520 Jules Bianchi (FRA) Marussia 1min37.62921 Giedo van der Garde (NED) Caterham 1min38.025 22 Max Chilton (GBR) Marussia 1min38.763Stay with Wheels24 for the 2013 Japanese GP weekend.