McLaren's Lewis Hamilton set the fastest practice time for Sunday's Korean Grand Prix after a wet first two sessions in Yeongam.
The Englishman finished 0.104 seconds ahead of teammate Jenson Button with newly-crowned world champion Sebastian Vettel in third.
"I think we are quick, the car feels good and Jenson showed in the last race that we can be competitive," said Hamilton, who is currently fifth in the drivers standings, 32 points behind Button.
"I have no doubts that we can challenge Red Bull but whether or not we can out-qualify them, which hasn't been done all year, will be interesting."
Ferrari's Fernando Alonso chose not to set a time in first practice but set the fourth fastest time in the second session.
