In a scintillating third practice session at Austin, reigning MotoGP champion Marc Marquez led the way ahead of fellow Honda rider Cal Crutchlow and Yamaha's Jorge Lorenzo.
Despite ominous dark grey clouds surrounding the Circuit of the Americas track, the MotoGP riders continued to improve their lap times in the all-important final practice session before qualifying.
The threat of rain was never far away, and Marquez was quick to set the pace as his quest to remain unbeaten at Austin remained on course. His improved best time of 2m03.302s saw him comfortably through automatically into the second phase of qualifying.
Crutchlow continued his strong form on the satellite LCR Honda, setting an impressive best lap of 2m03.490s, while Lorenzo will be much happier with his performance after setting a fastest time of 2m03.647s to lead his Yamaha teammate Valentino Rossi, who was fourth quickest.
Bradley Smith was on the pace once again for the Tech 3 team, the British rider lapping just 0.019s slower than Rossi and 0.107s quicker ahead of his teammate Pol Espargaro.
Aleix Espargaro showed some improved pace on the factory Suzuki, taking the top spot for a short time in the session and eventually ending with the seventh best time of 2m03.790s.
Ducati rider Andrea Dovizioso had a nervous FP3, but still booked his place in Q2 along with Marc VDS rider Scott Redding in ninth and Pramac Ducati's Danilo Petrucci in 10th place.