World champion Sebastian Vettel fired an ominous warning of intent as he shot his way to the fastest time in final practice Saturday for the Korean Grand Prix.
The runaway leader in the drivers' championship pipped estranged team-mate Mark Webber to the quickest time by 0.137sec with his 1min 37.881sec lap at a sunny Yeongam.
The Red Bull pair were followed by Mercedes duo Nico Rosberg and Lewis Hamilton, who dominated the two practice sessions on Friday.
There was a hairy moment for Vettel, who is 60 points clear in the title race, in the final quarter of the session when he ran wide at turn 13 and picked up dust as he pushed too hard.
Ferrari's Fernando Alonso, Vettel's nearest challenger in the title race, was fifth-fastest, followed by Romain Grosjean for Lotus and Alonso's team-mate Felipe Massa.
Grosjean's team-mate Kimi Raikkonen, Nico Hulkenberg of Sauber and McLaren's Jenson Button rounded out the top 10.
Qualifying takes place later Saturday.