Championship leader Nico Rosberg edged out Red Bull's Daniel Ricciardo to go fastest during Friday afternoon's practice session at the Circuit of the Americas.
Rosberg topped the session on a 1:37.358 with the super-soft tyre, which was 0.194s quicker than Ricciardo's best time -- suggesting Red Bull could run the world champions close this weekend. Hamilton, who had topped the morning session, had to settle for third 0.291s behind his teammate and title rival. Rosberg, who leads the championship by 33 points, will hope his advantage over Hamilton is a sign of things to come this weekend as he looks to claim a victory that would take him another step closer to a maiden world championship.
Sebastian Vettel finished fourth ahead of Max Verstappen in the other Red Bull, though Ferrari will be worried about the 0.6s gap to Ricciardo ahead. Force India pair Nico Hulkenberg and Sergio Perez finished sixth and seventh, ahead of McLaren's Jenson Button and Fernando Alonso, suggesting they have recovered from their Japan setback last time out. Kimi Raikkonen rounded out the top ten 1.5s off the pace, though he was the first man out on the super-soft tyres for qualifying simulations and ran wide at the penultimate corner, meaning he failed to set a representative time.
Carlos Sainz finished 11th for Toro Rosso, but ended his session with a spin through the twisty first sector. Kevin Magnussen was 12th ahead of Felipe Nasr's Sauber, who rounded off an impressive day with 13th. Williams pair Valtteri Bottas and Felipe Massa finished either side of 15th-place Daniil Kvyat, though the Grove team rarely shows its true pace on a Friday.
Jolyon Palmer finished 17th in a session which saw him suffer a strange spin on the exit of Turn 8. Romain Grosjean's Haas was the next man up in 18th, though the American team will be worried by what appeared to be a large chunk of debris falling from the rear of his car mid-way through the session. Esteban Ocon's Manor finished 19th despite an early spin in the gravel.
Esteban Gutierrez finished 20th in the other Haas, with Sauber's Marcus Ericsson and Manor's Pascal Wehrlein rounding off the table. Wehrlein was playing catch-up in the afternoon after giving up his Manor to Jordan King for the morning session.