Although the session started on a very wet Yeongam track, the track began to dry out mid-way through practice. However, conditions remained difficult for the drivers as the surface was extremely slippery.
Hamilton made the best of the track conditions, crossing the line with a 1:50.828 to edge his team-mate Button by 0.104s. But it was McLaren's gap to their rivals that caught the eye.
Newly-crowned World Champ, Sebastian Vettel, may have finished up in third place, however, he was 1.818s slower than Hamilton while Fernando Alonso was a further 0.128s off the pace.
Despite the conditions there wasn't any major drama except for Nico Rosberg's incident. The German got his braking wrong into Turn 1, went wide through the corner and collected Jaime Alguersuari as the STR driver left the pits.
Although there were heavy clouds overhead, it was not raining as Practice Two got underway in Korea with the track temperature sitting at just 19'C. Jaime Alguersuari led the field out with several drivers practicing starts at the end of the pit lane. The Toro Rosso driver also posted the first time, a 2:00.067.
Pastor Maldonado and Vitaly Petrov each had a turn in the P1 slot before Sebastian Vettel hit the front followed by Sebastien Buemi, then Jenson Button and Vettel again. Button hit the front again then Lewis Hamilton before Button returning to the P1 slot with three fastest sector times and a 1:51.798.
Michael Schumacher ventured out after a gearbox change and took 11th place before heading back in. Felipe Massa joined the list of those running wide at Turn 11 but, like those before him, no damage as it is a large run-off area.
Hamilton hit the front and then lowered the benchmark time as he stayed ahead of Button, Vettel, Mark Webber, Fernando Alonso and Buemi. A strong run saw Alguersuari slot into fourth place while Massa made it into the top ten. With absolutely no rain and almost no spray coming up from behind the cars, Webber improved to fourth place and then ran off the track on his next lap. Alonso returned to the action, taking fifth and then third. However, he was 1.946s behind pace-setter Hamilton. Vettel overhauled the Ferrari driver, 0.039s up.
Nico Rosberg, getting his braking all wrong, went sliding wide through the first corner and hit Alguersuari side on as the Toro Rosso driver left the pits. Rosberg, with a damaged front wing lodged under his car, pulled over on the side of the track. Game over.
Hamilton ventured out with 20 minutes left in the session, putting on another set of intermediate tyres. Hamilton and his rivals, though, were not able to improve their times as the track, while drying out, was greasy underfoot. There were several spinners during this period with Alonso, Bruno Senna, Buemi and Massa all having a turn.
There were a few tentative trips around the track as some, such as Alonso, Webber and Hamilton, opted for a slick tyre run. None of them, though, stayed out for more than a lap or two as it was too tricky. The session ended with Hamilton in front with a 1:50.828 and Button second, just 0.104s behind. Vettel was third, a massive 1.818s off the pace.
01. Lewis Hamilton McLaren-Mercedes 1m50.828 26 laps
02. Jenson Button McLaren-Mercedes 1m50.932 + 0.104 19 laps
03. Sebastian Vettel Red Bull-Renault 1m52.646 + 1.818 30 laps
04. Fernando Alonso Ferrari 1m52.774 + 1.946 25 laps
05. Mark Webber Red Bull-Renault 1m53.049 + 2.221 27 laps
06. Jaime Alguersuari Toro Rosso-Ferrari 1m53.402 + 2.574 25 laps
07. Felipe Massa Ferrari 1m53.707 + 2.879 24 laps
08. Nico Rosberg Mercedes 1m53.914 + 3.086 18 laps
09. Sebastien Buemi Toro Rosso-Ferrari 1m53.948 + 3.120 27 laps
10. Paul di Resta Force India-Mercedes 1m53.957 + 3.129 32 laps
11. Vitaly Petrov Renault 1m54.200 + 3.372 26 laps
12. Adrian Sutil Force India-Mercedes 1m54.392 + 3.564 26 laps
13. Rubens Barrichello Williams-Cosworth 1m54.831 + 4.003 30 laps
14. Michael Schumacher Mercedes 1m54.965 + 4.137 21 laps
15. Bruno Senna Renault 1m55.187 + 4.359 28 laps
16. Sergio Perez Sauber-Ferrari 1m55.203 + 4.375 24 laps
17. Kamui Kobayashi Sauber-Ferrari 1m55.544 + 4.716 23 laps
18. Pastor Maldonado Williams-Cosworth 1m56.067 + 5.239 22 laps
19. Heikki Kovalainen Lotus-Renault 1m56.669 + 5.841 20 laps
20. Jarno Trulli Lotus-Renault 1m57.173 + 6.345 19 laps
21. Timo Glock Virgin-Cosworth 1m58.269 + 7.441 25 laps
22. Jerome D'Ambrosio Virgin-Cosworth 1m59.458 + 8.630 26 laps
23. Daniel Ricciardo HRT-Cosworth 1m59.958 + 9.130 19 laps
24. Tonio Liuzzi HRT-Cosworth 2m00.165 + 9.337 20 laps.