Sebastian Vettel laid down a major marker ahead of qualifying for the Korean Grand Prix as he attempts not only to become the first driver in 2012 to win three races in a row, but also to overhaul Fernando Alonso's slim championship lead.

Having led the way at the end of day one, the German - who closed to within four points of Alonso with victory in Japan a week ago - underlined Red Bull's new-found performance by bettering the field by half a second after a last gasp lap opened his advantage over McLaren's Lewis Hamilton. The Briton had also improved his best effort late on, but had no answer for Vettel, who clearly senses a third successive world title.

Vettel's 1min 37.642secs benchmark, the best lap of the weekend so far, was set as the entire field switched to Pirelli's supersoft compound in a final check of qualifying set-up, but the German had also been fastest while running on the weekend's harder rubber, clocking a time a couple of tenths better than Hamilton could manage. The Red Bull was faster than its rivals in all sectors, but markedly so in the final 'street circuit' section, where Vettel opened out mot of his advantage over Hamilton.

The Briton looked happier with his car this time around, having stalked away from it at the end of FP2 on Friday, but could not match Vettel in any phase of the hour-long session. McLaren still looks to be Red Bull's closest rival heading into qualifying, with Jenson Button backing up his team-mate in third place, albeit a further three-tenths adrift, while Lotus moved into fourth and fifth on the timesheets, with Romain Grosjean edging team-mate Kimi Raikkonen as both black-and-gold cars moved ahead of Fernando Alonso's Ferrari. Both Raikkonen and Alonso, who were divided by just 0.039secs, were a full second off the pace

Mark Webber took seventh spot, but missed most of the second half of the session with a mechanical issue that denied him a run on the softer rubber. Nevertheless, the Australian remained ahead of Felipe Massa, with Pastor Maldonado and Nico Hulkenberg rounding out the top ten.

Sergio Perez was eleventh in the best of the Saubers, just ahead of the Mercedes of Nico Rosberg and Michael Schumacher. Further back, Vitaly Petrov got the better of Caterham team-mate Heikki Kovalainen, while Charles Pic, who faces a ten-place grid drop after taking his ninth engine of the year, moving ahead of Marussia team-mate Timo Glock in the final moments.