Vettel holds position for now, just seven points ahead of his compatriot, but it is Mercedes rather than Ferrari who carry the momentum into Austin - particularly given the warm glow that comes from clinching their second straight constructors' title in Russia.
Rosberg too has form in the United States, and will be desperate to go one better than he managed last year, when he sealed pole and led for the opening third, only to eventually be denied by Hamilton.
"Being back at the factories and seeing everyone so happy was just the boost I needed after a tough Sunday in Russia," Rosberg, who retired in Sochi, says. "The whole team deserves this moment and what we've achieved together is really amazing. Hopefully this is just the start.
"With four races left and a big gap to Lewis, it's clear that the title is a long shot for me now. But it's not in me to give up or back down, so I'll be pushing flat out to the end and hopefully having some fun out there in the final few rounds this year. I really want to enjoy the next races, as our Silver Arrow is such a great car and gives me the chance to end the year with a few more wins.
"I got pole there last year, and I'm coming off the back of a really strong weekend in Russia in terms of my performance, so if I can repeat all of that then I'll be in a good position. Bring it on!"
Vettel, meanwhile, has an enviable record at Austin - he is the only man other than Hamilton to triumph, and can boast two podiums from F1's three visits. He struggled last year with Red Bull, however, coming home seventh as then team mate Daniel Ricciardo claimed a podium in third.
Speaking of Red Bull, the team could be in for a welcome boost this weekend after engine suppliers Renault used 11 of their remaining 12 engine development tokens on a much-needed upgrade. Having worked on reliability issues from the beginning of the season, this will mark the first quest for more horsepower to put the cars from Milton Keynes on better terms with their Mercedes- and Ferrari-engined opposition, and entails significant changes within the internal combustion engine and to the turbocharger.
Though the new ICE has passed its own reliability tests just recently, it is still not confirmed that the unit will actually be used in the race as doing so would entail further grid penalties for Ricciardo and team mate Daniil Kvyat. Renault will discuss the situation with Red Bull and Toro Rosso in the Austin paddock, prior to a final decision being taken.
Away from the track, it is also going to be a big weekend for both Marussia and Sauber.
Alexander Rossi will be a major talking point for the former, as he rejoins the team ahead of his home race. It will be the first time an American driver has competed in F1 on home turf since Scott Speed at Indianapolis in 2007, ensuring the spotlight will be firmly on Marussia - and Rossi - this weekend.
"Of course I'm going to face a lot of media interest which will add to the pressure this weekend," Rossi admits, "but that's why I'm racing and I can't wait to get back into the car and to push as hard as I can in front of my home crowd.
"It's a huge deal for me, not only because it makes me extremely proud to be the first American driver to race on US soil since 2007, but also because it's the realisation of a goal that I, and the people around me, have been working towards for effectively 13 years. This weekend is an opportunity to reward their support and commitment as much as my own determination as a race car driver, and I'll be giving it my all."
Sauber, meanwhile, will be celebrating their 400th Grand Prix this weekend, a feat only five other teams in history have achieved.
Having made their debut in South Africa in 1993, the team have started all but three races since - Monaco in 1994, Brazil in 2000 and the United States in 2005 - bringing them to the landmark total this weekend.
"Big congratulations from me on this achievement," said Marcus Ericsson, one half of the team's 2015 line-up. "Celebrating the 400th GP is amazing. I am very glad to be part of the Sauber F1 Team, and also having the trust from everyone. I believe that my biggest Sauber moment is still in the future - I will be driving for the team for another season, and I hope this will come soon!"
The big news for Ericsson and the rest of the field this weekend is that it is expected to be wet, with bad weather forecast throughout the weekend. Thunderstorms are predicted for Thursday, Friday and Saturday, with Sunday anticipated to deliver the least rainfall. Temperatures are expected to be fairly consistent around 22-24 degrees Celsius.
Such forecasts might mean that Pirelli's two chosen tyre compounds for the weekend, the white-marked medium and yellow-marked softs, get very little track time.
"With the driver's championship entering a decisive phase there's obviously going to be a lot of attention on the race, and we can think of no better place to showcase Formula One," Pirelli's motorsport director Paul Hembery says.
"The track configuration and tyre choice offer plenty of opportunities for overtaking and strategy, with a reasonably short pit lane time loss too, so we could be on for quite an unpredictable race, which is what people want to see. It's rarely an open and shut competition, as we saw from the wide variety of strategies used last year."
The forecasts also mean we are set for our first fully wet sessions at Austin, already an immensely challenging and technical circuit. Boasting 20 corners of a very varied nature, and a tricky uphill braking area at Turn 1, the anticlockwise circuit features three long straights that tend to cool down the tyres, making the braking areas critical, as tyre temperature will have dropped slightly. This also then affects the turn-in into fast corners, as the compound has to get back up to temperature very quickly - an effect that could be exacerbated in the wet.
The Circuit of The Americas also places a premium on front-end mechanical grip to facilitate sharp turn-in during the fast direction changes that characterise the first half of the lap.
As was the case last year, the circuit will feature two DRS zones: the first is on the long run between Turns 11 and 12, while the second is activated just after the final left-hander of Turn 20, coming onto the main straight.
Sunday's race will run over 56 laps or 308.896 kilometres (191.942 miles), and will start at 1400 hours local time (1900 GMT).
Title permutations: How Hamilton could wrap it up in Austin
