Formula One championship leader Nico Rosberg put more pressure on teammate and rival Lewis Hamilton by posting the fastest lap in Friday's practice sessions as he seeks to tighten his grip on a potential first title.
"As we've seen this year, qualifying isn't all important", Rosberg added.
Nico Rosberg has dismissed talk of winning his maiden drivers' world championship preferring instead to focus on winning one race at a time.
But Hamilton will be boosted by topping the P1 timesheet for the first time since the August break and with the psychological lift of knowing he has won three of the four F1 races to be held at the Circuit of the Americas. "Why don't we try this for a change?' I think Lewis had a good point".
Nico Rosberg, who leads his Mercedes team-mate defending champion Lewis Hamilton by 33 points with four races remaining, wound up fastest ahead of Ricciardo.
Wearing glasses and smiling, Hamilton was clearly at home and happy to be back on American soil ahead of Sunday's race at the Circuit of the Americas where he clinched his third title past year.
"I am in the position right now where there are still a lot of points available so I'm going to give it everything I've got and still have the belief that anything is possible", said Hamilton. "It was much appreciated, and I hope tomorrow we can deliver another great race".
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Australia's Daria Gavrilova has continued her strong form with a 6-2 6-2 first-round upset of Lucie Safarova at the Kremlin Cup. Cuevas beat Slovak qualifier Jozef Kovalik 6-4, 7-6 (4), firing 11 aces in their second-round match.
The Ferrari driver, sixth in the standings, said he would love to be in Hamilton's position.
Like the previous two seasons, Mercedes has dominated the field with 15 wins in 17 races.
Hamilton is without a victory since the German Grand Prix in July and he faces an uphill task to wrestle the championship momentum back in his favour.
Bit Rosberg showed just who is boss in the second session as if Hamilton needed reminding that he still has it all to do. Fortunately the conditions are looking good this year, with Sunday's race predicted to be run under partly cloudy skies and in 86 degrees F (30 degrees C) peak temperature.
Hamilton, victor in three of the last four races at the Texan track including 2015 when he took his third title, was quickest in the morning in 1:37.428 with Rosberg second, 0.315 slower.
Rosberg, chasing his 10th win of the season on Sunday while Hamilton has six, said he had lost speed in the first sector but played down the significance of the Saturday duel.