Jenson Button was quickest as McLaren once again secured a one-two in practice for the Korean Grand Prix.
Button and team-mate Lewis Hamilton were clear of the field in the damp conditions of FP2, but they once again dominated the headline times in the dry as Button set a time of 1:36.910 to head Hamilton by 0.289s. Mark Webber was third but 0.8s behind Button, with Fernando Alonso fourth over a second back.
World Champion Sebastian Vettel was only ninth fastest and 2.7s off the pace as he was unable to set a competitive time on supersoft tyres. Twice Vettel went for a flying lap and twice he came up behind Jaime Alguersuari's Torro Rosso, leading to some gestures from the cockpit once he finally found a way past.
After the wet running that took place on Friday, the track was immediately busy as soon as the lights went green. Both Red Bulls and Mercedes were keen to push on and didn't pit after their installation laps, with Vettel the first man to dip under the 1m40s barrier. He was barely able to improve on that time though despite completing 22 laps, as the congested track made traffic a problem.
Hamilton was soon clear at the top though and came out for a run later in the session on soft tyres to lower the mark. He seemed to have the edge on his team-mate throughout the hour as he could always respond as the pair traded lap times, but Hamilton also found himself struggling with traffic during his qualifying simulation, allowing Button to steal top spot with his final lap.
Bruno Senna marked his birthday with a spin, running a touch wide on the exit of turn 13 and putting two wheels on to the wet Astroturf. Having tried to catch the car it fishtailed in to a spin, clipping the concrete wall with his front wing but being able to recover the car back to the pits.