YEONGAM, South Korea (AP) — Mercedes driver Lewis Hamilton set the fastest lap in Friday's opening practice session for the Korean Formula One Grand Prix, beating the times of Red Bull pair Sebastian Vettel and Mark Webber.

Hamilton's time of 1 minute, 39.630 seconds around the Yeongam circuit was just three-hundredths of a second faster than runaway Formula One championship leader Vettel, with Webber also within two-tenths of a second of Hamilton.

Hamilton's Mercedes teammate Nico Rosberg was fourth fastest, followed by the McLaren of Jenson Button and Ferrari's Fernando Alonso.

Many drivers had excursions off the unrubbered and dusty track, with the Lotus' Kimi Raikkonen having a heavy side impact with a tire wall at the very end of the session.