Rosberg out to turn the tables on Hamilton
Momentum in the Mercedes camp has been distinctly one-way of late: while Rosberg has floundered, committing mistakes in Italy and Russia and suffering mechanical woes in Singapore, Hamilton has been irrepressible. In the last four races the Briton has taken four wins and a maximum score of 100 points, whilst Rosberg has managed just 54. That has lifted Hamilton 17 points clear in the title fight - the biggest deficit Rosberg has faced all year. When Hamilton dominated practice in Austin, the signs appeared ominous for Rosberg.
However, what transpired in qualifying went some way to resetting the balance - not only did Rosberg claim his ninth pole of the season, he did so with a comfortable advantage of over three-tenths on Hamilton, who later admitted he had no answer to the German's pace.
As welcome as edging Hamilton will be for Rosberg, the real challenge will be repeating the feat on Sunday. If he wins - or at the very least outscores Hamilton - then his title hopes remain in his own hands. Lose out to Hamilton, however, and he will suddenly be very much reliant on the Briton slipping up in the final two rounds. The stakes therefore couldn't be higher - and it is under that pressure that Rosberg needs to flourish if he is to truly turn the tables and reclaim the initiative.
Vettel on the charge
It's been a rather strange weekend for the reigning world champion. Instead of working through a normal practice schedule - and then attempting to qualify as high as possible - Vettel has focused entirely on race set-up, owing to the fact that he'll start Sunday's Grand Prix from the pit lane following a complete power unit change.
It's been unusual to see Vettel - who won this race last year - languishing at the bottom of the timesheets, but on the plus side he's done considerably more high-fuel race simulation runs than any other driver on the grid, and in a tightly-matched field that can only be a good thing, even if the man himself doesn't feel overly optimistic about his chances:
"In the race I think we can move up - our race pace seems okay - but it will be tight. It will be difficult to overtake, as we don't have the ideal straight line speed, but hopefully we can get some points tomorrow. Seventh would be a good result."
Wherever he ends up, it will certainly be entertaining watching him try to come through the field.
After the one-stop race we saw in Russia, we're set to return to multi-stop racing in the United States with Pirelli expecting three to be the optimum strategy for the 56-lap event.
However, with traffic likely to be an issue, the Italian manufacturer is quick to point out that three stops will probably only work for the fastest cars that are able to overtake cleanly. Those cars would start on the softs, stop for new softs around lap 12, take on a final set of softs around lap 25, and finally stop for mediums on lap 35.
For those starting outside the top ten, who have the option to start on the medium tyre, a strategy that is almost as quick as a three-stopper would see the drivers starting on medium, pitting for softs around lap 22, then for mediums again around lap 36. A long first stint on the medium has the advantage of gaining track position on those who start on softs and have to pit earlier. This track position could then be consolidated on a soft tyre middle stint.
Hamilton locking up
Given his penchant for braking hard and late into corners, it's not unusual to see Lewis Hamilton lock a front tyre. But after dominating all three practice sessions, the Mercedes driver seemed to be locking up more than usual in qualifying.
"I really struggled with braking," the Briton admitted. "When you look at the brake temperatures, the left brake was always around 100 degrees less than the right front brake. It just kept catching. No matter what I did, even if I braked earlier and tried to save it, it would still lock. So that was perhaps where I was losing a lot of the time."
A mistake at Turn 12 on his single Q2 run means Hamilton will start the race with a slight flat spot - and a slight vibration - on his left front tyre, but according to the 2008 world champion, that's not the main problem.
"Well the vibration isn't that bad - it's a minor flat spot. They'll rebalance it and hopefully I won't feel too much with it. The issue is just locking. If I can't fix that left brake, then that will be a continuing issue throughout the race. And obviously flat spots lead to blistering so I've got try and make sure we can fix that this evening."
Although major work is not allowed under parc ferme conditions, certain changes can be made to the brakes, and Hamilton is hopeful that these will fix his issues. If they don't he may find it difficult to live with team mate Nico Rosberg in the race.
Mixed prospects for the two 'home' drivers
Mexico joins the F1 calendar in 2015, but until then neighbouring Austin is very much the home race for Force India's Sergio Perez, Sauber's Esteban Gutierrez and the legions of Mexican fans who cross the border to visit the Circuit of The Americas.
However, the two drivers look set to have very different races. Perez will start just outside the points-paying positions and just in front of McLaren's Jenson Button - a man he needs to beat if Force India are to stand any chance of denying the Woking team fifth in the constructors' table. Gutierrez, meanwhile, is down in 15th on the grid and will be extremely hard pushed to break into the top ten, especially with the likes of Vettel starting behind him. Despite their differing prospects, what's certain is that both men will be cheered loudly all the way to the chequered flag.
Sauber finally on course for points…
It has been a truly miserable season for Sauber. The proud Swiss team, on the grid since 1993, have failed to score in any of the 16 races so far, and that marks the longest barren run in their history. But in Austin Adrian Sutil gave Monisha Kaltenborn's squad hope by breaking into Q3 for the first time this year and qualifying tenth (which became ninth once Jenson Button's five-place gearbox penalty was applied).
With evenly matched cars all around him - not to mention the likes of Sebastian Vettel coming through the field - it will be extremely tough for Sutil to hang on to a top-ten position, but at least the German feels comfortable in his car - a real rarity this season.
"We have to get the maximum out of this position tomorrow," said Kaltenborn unequivocally after qualifying. Can Sutil deliver what are likely to rank amongst the hardest earned points of his career?
…as is Maldonado
His home town of Maracay may be more than 3,500 kilometres from Austin, but the United States Grand Prix is the closest that Pastor Maldonado will race to his native Venezuela all season, so what better way to celebrate than to finally score his first points of the year? The Lotus driver will start Sunday's race from a season-high tenth on the grid and has every chance of bettering his best finish of 2014 - 12th.
"The car feels more solid and together than it has for the last few races which meant I was able to push more than usual," he said after qualifying. "We know we work better in the faster corners - just as we saw in Barcelona - and I think there is still more pace in the car. We're well placed for tomorrow; we need to have a good strategy, stay relaxed and calm and then let's fight for the points. I think we have a great chance to score and that will be the main focus."