The German driver, who was 1.4 seconds quicker in first practice and 0.7 seconds ahead in second practice, finished 0.254 seconds faster than McLaren’s Lewis Hamilton.
Pastor Maldonado pushed his Williams to the limit to finish in third position ahead of championship hopeful Alonso at the brand new Circuit of the Americas.
Although Ferrari has not been able to match Red Bull’s dominant practice pace, the team are working hard to prepare for the race.
The Italian outfit were spotted scrubbing their tyres ahead of qualifying by doing one lap on them and then pitting again. The technique takes the shine off the tyres, meaning they may drive a bit faster later this weekend.
Sauber’s Sergio Perez, who will be replacing Hamilton at McLaren next year, had a collision with Charles Pic.
The Mexican was flying after going purple in the first sector and tried to dive down the inside of the Marussia driver. Unfortunately, there was not space and Perez clipped the back of the car, spinning Pic round and breaking his own front wing.
Jean-Eric Vergne ended his session early after breaking the front suspension of his Toro Rosso. With the wheels facing inwards and not responding, the mechanics will be working hard to try to fix the car before qualifying.
Romain Grosjean also had his practice terminated after problems with his Lotus. If the team is forced to change the gear box, that will mean a five-place grid penalty for the Frenchman.
Turn 19 will prove decisive in qualifying. It proved challenging for the drivers on Friday and today continued in a similar vein, with Timo Glock, Vettel and Alonso all running wide on the corner.
With HRT’s future in jeopardy after their owners, the investment group Thesan Capital, said they were up for sale, it’s been a difficult weekend for the team.
Drivers Pedro de la Rosa and Narain Karthikeyan ended at the bottom of the grid after both struggling to get heat into their tyres. The drivers have to get within 107 per cent of the fastest time in first qualifying to be allowed into Sunday’s race.
1. Sebastian Vettel (Ger) Red Bull 1:36.490
2. Lewis Hamilton (Gbr) McLaren
3. Pastor Maldonando (Ven) Williams
4. Fernando Alonso (Spa) Ferrari
5. Nico Rosberg (Ger) Mercedes
6. Felipe Massa (Bra) Ferrari
7. Mark Webber (Aus) Red Bull
8. Sergio Perez (Mex) Sauber
9. Nico Hulkenberg (Ger) Force India
10. Jenson Button (Gbr) McLaren
11. Bruno Senna (Bra) Williams
12. Michael Schumacher (Ger) Mercedes
13. Kimi Raikkonen (Fin) Lotus
14. Kamui Kobayashi (Jpn) Sauber
15. Daniel Ricciardo (Aus) Toro Rosso
16. Paul di Resta (Gbr) Force India
17. Romain Grosjean (Fra) Lotus
18. Jean-Eric Vergne (Fra) Toro Rosso
19. Timo Glock (Ger) Marussia
20. Vitaly Petrov (Rus) Caterham
21. Heikki Kovalainen (Fin) Caterham
22. Charles Pic (Fra) Marussia
23. Pedro de la Rosa (Spa) HRT-F1
24. Narain Karthikeyan (Ind) HRT-F1
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BIOGRAPHY: Ethan Hazard
BIOGRAPHY: Daniel Sturridge