Sebastian Vettel finished the final practice session at Austin on top ahead of his teammate Mark Webber. The German lapped his RB9 in 1:36.733 to outpace Webber's lap time of 1:36.936 by two tenths of a second. And there was more to come from the four time world champion, particularly in sector one, had his race engineer Rocky not told him to 'minimise' running for some unknown reason.
An interesting thing to note from the session was that drivers were able to better their time on option tyres on their second flying lap.
Lewis Hamilton was third fastest after setting his fastest lap late in the session. It would have brought some consolation for the Brit who seemed to be struggling with oversteer on hard tyres.
Nico Hulkenberg was fourth fastest after earlier leading the medium tyre runners. He lapped his Sauber C32 in 1:37.272 to beat Lotus' Romain Grosjean. Jenson Button was sixth fastest in the session to again prove that McLaren have really improved in the last few races.
Nico Rosberg was seventh fastest after clocking the Circuit of the Americas in 1:37.578. Sergio Perez was eight in the second McLaren while Valtteri Bottas finished the session in ninth place. The Grove based outfit have looked particularly strong this weekend, especially in morning sessions. It would be interesting to see where they qualify this afternoon. Adrian Sutil rounded up the top 10.
Ferrari's form was bit of a concern for second straight Grand Prix and neither of their cars could post a lap time which would put them in top 10 in the timesheets. Fernando Alonso was 11th while Felipe Massa was 17th after admitting to Rob Smedley that his F138 was ''extremely slow''.
Gutierrez was 12th fastest in the second Sauber while Heikki Kovalainen finished FP3 in 13th. The Finn was within four tenths off Grosjean on hard tyres but felt back when everyone put the white medium rubber on.
Maldonado and Ricciardo were 14th and 15th for Williams and Toro Rosso respectively. Among the backmarkers, Pic led Giedo Van der Garde while Bianchi was faster of the two Marussias in 21st.