Sebatian Vettel topped the timesheets in Saturday's final practice in Austin which saw Lewis Hamilton take second and Fernando Alonso saved by a late charge.
Practice Three begun in much the same way the previous two had with drivers flying off the track at Turn 19 even whilst on their installation laps. Jean-Eric Vergne was the early pace-setter as Toro Rosso went straight into the action with Daniel Ricciardo taking second behind his team-mate.
Vergne was overhauled by Nico Rosberg who in turn was beaten by Michael Schumacher. The seven-time World Champ posted a 1:39.483 to hold the P1 slot after the first 15 minutes of action. However, only seven drivers had set times.
There were early woes for Sergio Perez and Charles Pic as the faster Sauber driver attempted to find the gap that wasn't there down the inside of Turn Seven. Instead he tagged Pic, pushing the Marussia around before spearing it in the side. A shake of the head from their mechanics as both cars are damaged.
Back at the front the big boys came out to play with Jenson Button sliding into second place, 0.3s short of Rosberg's P1 time. He continued lapping to take first, 0.2s up on the German's time. His team-mate Lewis Hamilton worked his way up the timesheets from tenth to sixth and then to fourth while Sebastian Vettel was 17th on his first effort. He went on to improve to 15th and then 11th.
Button meanwhile lowered the benchmark time to a 1:37.659 while Hamilton climbed to second behind his team-mate before taking first off him by 0.046s. Vettel found some pace and slotted into third behind the McLaren duo.
Vergne was the first casualty of the session as he broke his front suspension when he hit a kerb. He was forced to park his Toro Rosso out on track with both front tyres pointing inwards.
Fernando Alonso had a late start to his morning as the Spaniard only put in his first lap time with 20 minutes remaining. As such he caught the yellow flags from Vergne' stricken car and despite his efforts struggled to move into the top 10. In fact, Alonso was pushing so hard he had several off track moments, which also ruined what could have been a solid lap on the medium tyres.
The final few minutes saw all the drivers swap to the medium compound which take several laps to heat up. But once he had heat in the rubber, Vettel jumped into the lead with a 1:36.490 while Hamilton took second off Pastor Maldonado and the very late-improving Alonso.
01 Sebastian Vettel Red Bull 1:36.490 18 laps
02 Lewis Hamilton McLaren 1:36.748 0.258 20 laps
03 Pastor Maldonado Williams 1:37.001 0.511 21 laps
04 Fernando Alonso Ferrari 1:37.180 0.690 21 laps
05 Nico Rosberg Mercedes 1:37.247 0.757 24 laps
06 Felipe Massa Ferrari 1:37.262 0.772 27 laps
07 Mark Webber Red Bull 1:37.298 0.808 18 laps
08 Sergio Perez Sauber 1:37.415 0.925 20 laps
09 Nico Hulkenberg Force India 1:37.495 1.005 20 laps
10 Jenson Button McLaren 1:37.538 1.048 20 laps
11 Bruno Senna Williams 1:37.569 1.079 21 laps
12 Michael Schumacher Mercedes 1:37.760 1.270 21 laps
13 Kimi Raikkonen Lotus 1:37.765 1.275 26 laps
14 Kamui Kobayashi Sauber 1:37.953 1.463 23 laps
15 Daniel Ricciardo Toro Rosso 1:38.547 2.057 23 laps
16 Paul di Resta Force India 1:38.653 2.163 22 laps
17 Romain Grosjean Lotus 1:38.753 2.263 11 laps
18 Jean-Eric Vergne Toro Rosso 1:39.689 3.199 12 laps
19 Timo Glock Marussia 1:40.407 3.917 23 laps
20 Vitaly Petrov Caterham 1:40.753 4.263 19 laps
21 Heikki Kovalainen Caterham 1:41.011 4.521 19 laps
22 Charles Pic Marussia 1:41.466 4.976 19 laps
23 Pedro de la Rosa HRT 1:43.563 7.073 21 laps
24 Narain Karthikeyan HRT 1:44.043 7.553 23 laps