Sebastian Vettel quickest in first practice of US Grand Prix

Red Bull's Sebastian Vettel has shown his intent ahead of the United States Grand Prix on Sunday by clocking the fastest time in the first practice in Austin, Texas.

McLaren driver Lewis Hamilton, who sped off the track to avoid clashing with Michael Schumacher on the exit of turn nine, looked poised to take the best time with 12 minutes left to go in the practice.

Despite his impressive session, Vettel, who initially seemed to be struggling with the handles of his car, managed to whip around the track and finish the circuit 1.4 seconds faster than the Brit.

Ferrari's Fernando Alonso, who is Vettel's biggest challenger for the title, clocked the third quickest time, which was 2.2 seconds behind the Red Bull driver, who currently leads by 10 points in the drivers' rankings with two races left to go in the season.

First practice standings: 1. Sebastian Vettel (Red Bull) - 1:38.125 2. Lewis Hamilton (McLaren) - 1:39.543 3. Fernando Alonso (Ferrari) - 1:40.337 4. Jenson Button (McLaren) - 1:40.528 5. Mark Webber (Red Bull) - 1:40.650 6. Felipe Massa (Ferrari) - 1:40.966 7. Nico Hulkenberg (Force India) - 1:41.023 8. Kamui Kobayashi (Sauber) - 1:41.036 9. Nico Rosberg (Mercedes) - 1:41.159 10. Sergio Perez (Sauber) - 1:41.473 11. Paul Di Resta (Force India) - 1:41.783 12. Daniel Ricciardo (Toro Rosso) - 1:41.825 13. Jean-Eric Vergne (Toro Rosso) - 1:41.833 14. Kimi Raikkonen (Lotus) - 1:41.880 15. Romain Grosjean (Lotus) - 1:41.998 16. Pastor Maldonado (Williams) - 1:42.539 17. Michael Schumacher (Mercedes) - 1:42.588 18. Charles Pic (Marussia) - 1:43.288 19. Heikki Kovalainen (Caterham) - 1:43.443 20. Vitaly Petrov (Caterham) - 1:43.522 21. Timo Glock - (Marussia) - 1:44.464 22. Bruno Senna (Williams) - 1:44.548 23. Pedro de la Rosa (HRT) - 1:46.917 24. Ma Qinghua (HRT) - 1:48.559