F1: Sebastian Vettel returns to the top of the table in Japan after Lewis Hamilton briefly threatened the 2013 world champion in waiting

The Mercedes duo of Hamilton and Nico Rosberg topped the timesheets in first practice before Vettel and Mark Webber followed suit in second practice with a Red Bull one-two

Sebastian Vettel finished second practice with the fastest lap time at Suzuka (GETTY IMAGES)

Sebastian Vettel enjoyed the perfect scenario in second practice for the Japanese Grand Prix that if repeated in Sunday's race will see him crowned Formula One world champion for a fourth consecutive time.

At a Suzuka circuit where Vettel has been on pole at the last four races, winning three of them, the 26-year-old finished top of the timesheet in his Red Bull.

After Lewis Hamilton spearheaded a Mercedes one-two in the opening 90-minute session, so Vettel followed suit in the second run as he finished 0.168secs faster than team-mate Mark Webber.

With the teams switching to the faster medium-compound Pirelli tyres for a spell in FP2, after exclusively running on the slower, harder rubber in FP1, Vettel posted a time of one minute 33.852secs.

With a 77-point lead over his nearest rival in Ferrari's Fernando Alonso, Vettel can make it four championships in a row with a fifth straight win and if the Spaniard is ninth or lower.

In practice, Alonso could only finish 10th quickest, 1,235secs down on Vettel's pace as the German was the only driver to dip below the one minute 34secs mark.

Behind Webber was Mercedes' Nico Rosberg, a quarter of a second back, with Kimi Raikkonen fourth in his Lotus, albeit with his session cut short by 35 minutes as he spun into a gravel trap.

The Finn was followed by team-mate Romain Grosjean, with Hamilton only sixth and with a time three tenths of a second slower than his best in first practice.

Daniel Ricciardo appears solid in his Toro Rosso, the Australian seventh fastest ahead of Felipe Massa in his Ferrari, McLaren's Jenson Button and then Alonso who suffered a high-speed spin on the approach to the second Degner turn, although he managed to recover.

Force India's Paul Di Resta, one of many who suffered a minor spin, was 14th, just 0.066secs ahead of team-mate Adrian Sutil.

For a driver whose F1 future is in doubt, McLaren's Sergio Perez did himself no favours with a sizeable shunt on entry to one of Suzuka's renowned turns, the Spoon Curve.

Clipping the astroturf to his right on the outside apex of the long left-hander, and in hitting the brakes, Perez skewed sideways before slamming the right-hand side of his car into a barrier.

That incident came moments after Williams' Pastor Maldonado suffered his second shunt of the day, on this occasion losing his car on entry to the second Degner where he buried the nose in a tyre wall.

That made Maldonado the third driver to crash at the same corner as Marussia's Jules Bianchi and Giedo van der Garde did so in FP1.

For Bianchi, his car was damaged to such an extent, the team were unable to carry out the necessary repairs in time for FP2, instead concentrating on building up the spare chassis in time for final practice tomorrow.

As for Maldonado in first practice, the left-rear wheel of his car became inexplicably detached.

Approaching Spoon, Maldonado ran wide, but as he attempted to make his way back on track, the Venezuelan was forced into a spin as the wheel worked loose, it then bouncing into a gravel trap where it was recovered by marshals.

PA