Championship leader Mark Webber led the way in a wide-open second practice session for the Korean Grand Prix, which saw Red Bull, Ferrari, McLaren and Renault all represented in the top four.
With the circuit conditions getting ever faster – and more familiar to the drivers – the afternoon session saw pretty much every frontrunner leading the way at some point. Fernando Alonso was among the early pacesetters, as Ferrari showed its hand after a typically cautious Friday morning, while Michael Schumacher also popped up on top for Mercedes for a brief spell mid-session between McLaren duo Lewis Hamilton and Jenson Button swapping the lead.
Sebastian Vettel's first lap on soft tires was wasted by a trip off the road dodging Jarno Trulli's Lotus, but he hit the front next time around, deposing Button. Webber had a similar experience – spinning at the sweeping Turn 12 before regaining his composure and setting the fastest time on his next lap. Bar a quick return to the top by Hamilton, the Australian would remain in front for the rest of the session.
Alonso moved back up to second between Webber and Hamilton, with morning second-place man Robert Kubica fourth for Renault this time. Button's car required attention in the McLaren pit after an overheating rear end forced the crew to deploy fire extinguishers. But the damage was soon repaired and the reigning champion returned to take fifth.
Felipe Massa was sixth for Ferrari, despite complaining about poor handling in the final sector, with Vettel seventh in the end ahead of Renault's Vitaly Petrov, Mercedes' Nico Rosberg and the two Saubers.
It was another troubled session for Hispania at the tail of the field. Bruno Senna only got out in time to complete three laps following his morning problems, and Sakon Yamamoto caused a brief red flag after spinning, brushing the wall and stalling in the tight confines of the final corners.
Pos Driver Team Time Laps
1. Webber Red Bull-Renault 1:37.942 23
2. Alonso Ferrari 1:38.132 + 0.190 30
3. Hamilton McLaren-Mercedes 1:38.279 + 0.337 29
4. Kubica Renault 1:38.718 + 0.776 29
5. Button McLaren-Mercedes 1:38.726 + 0.784 19
6. Massa Ferrari 1:38.820 + 0.878 32
7. Vettel Red Bull-Renault 1:39.204 + 1.262 22
8. Petrov Renault 1:39.267 + 1.325 28
9. Rosberg Mercedes 1:39.268 + 1.326 29
10. Kobayashi Sauber-Ferrari 1:39.564 + 1.622 26
11. Heidfeld Sauber-Ferrari 1:39.588 + 1.646 25
12. Schumacher Mercedes 1:39.598 + 1.656 26
13. Barrichello Williams-Cosworth 1:39.812 + 1.870 35
14. Liuzzi Force India-Mercedes 1:39.881 + 1.939 27
15. Sutil Force India-Mercedes 1:39.971 + 2.029 22
16. Hulkenberg Williams-Cosworth 1:40.478 + 2.536 30
17. Alguersuari Toro Rosso-Ferrari 1:40.578 + 2.636 29
18. Buemi Toro Rosso-Ferrari 1:40.896 + 2.954 32
19. Kovalainen Lotus-Cosworth 1:42.773 + 4.831 29
20. Trulli Lotus-Cosworth 1:42.801 + 4.859 19
21. Glock Virgin-Cosworth 1:43.115 + 5.173 26
22. di Grassi Virgin-Cosworth 1:44.039 + 6.097 29
23. Yamamoto HRT-Cosworth 1:45.166 + 7.224 19
24. Senna HRT-Cosworth 1:46.649 + 8.707 3
All Timing Unofficial