Red Bull's Sebastian Vettel claimed his sixth pole position of the season to take a huge step towards his third drivers' championship.
The German leads Ferrari's Fernando Alonso by 10 points heading into tomorrow's race and victory would all but seal the title.
Alonso could only manage a ninth-place finish, but will start in eighth by virtue of Romain Grosjean's five-place grid penalty.
You can read how the action unfolded below.
5.48pmGood evening Formula 1 fans and welcome to Sports Mole's live coverage of a pivotal qualifying session in Texas.
5.52pmA slew of American celebrities and sports stars past and present are in tow for today's racing at the brand new Circuit of the Americas. Among the VIPs enjoying a pit-lane view is Hollywood director Ron Howard and former runner Michael Johnson. Former Friends star Matt le Blanc also looks like he's having a good time.
5.54pmVettel has dominated in practice. You just feel that all Alonso can do is keep the championship alive until next week and see what he can do in Brazil. Vettel had a sluggish start to the year, but has kicked into gear right when he's needed to.
5.59pmMcLaren boss Martin Whitmarsh has already voiced concerns regarding tyres. It takes time for them to warm up on this new track.
Q1Qualifying is now underway and Kimi Raikkonen is the man who starts us off.
Q1The Finn posts the early time of 1.41 to go ahead of Glock, Pic, Karthikeyan and De la Rosa.
Q1Vettel is ready to come out of the garage.
Q1Grosjean is the first man to break 1.40.
Q1Here comes Alonso...
Q1An average first sector for the Spaniard. He's eight tenths behind Grosjean's time.
Q1Massa goes second, with Alonso third. The tyres are warming up, though.
Q1We have just over eight minutes left and Grosjean still leads, ahead of Webber, Hulkenberg, Massa, Alonso and Button.
Q1Hamilton was struggling in the drop zone but has posted the ninth-fastest time. Kovalainen, De la Rosa, Karthikeyan, Petrov, Rosberg, Schumacher and Kobayashi are also down there.
Q1Vettel goes fastest with 1.37. Grosjean is second, followed by Massa, Hulkenberg, Webber, Senna, Button, Alonso.
Q1Schumacher posts 1.38 at the first time of asking. He's into 12th now.
Q1Karthikeyan comes to a standstill. He's 23rd anyway, and was likely to miss the cut.
Q1Final two minutes of qualifying. Hamilton goes top, with Vettel in second. Rosberg, Glock, Pic, Petrov, Kovalainen and De la Rosa are in the drop zone. There is a yellow flag out for Karthikeyan's car, to make things worse for them.
Q1Rosberg creeps into 17th and into the next session! Ricciardo is the man who drops out.
DRIVERS OUT:Ricciardo, Glock, Pic, Petrov, Kovalainen, De la Rosa, Karthikeyan
6.24pmVettel clocked the fastest time of 1.36.
Q2Q2 is now underway.
Q2Raikkonen posts 1.37. Senna is second, with Grosjean third.
Q2Vettel, Webber, Kobayashi and Perez are yet to get out onto the track for Q2.
Q2Hamilton goes first with a time of 1.36.
Q2Alonso is just in, while Vettel is just out. Expect that to change shortly...
Q2Five minutes left and Alonso is down into 12th. Meanwhile, Vettel smashes Hamilton's time by nearly one second to go top. Brilliant driving.
Q2Christian Horner was delighted with that lap from Vettel.
Q2Just over three minutes left and Senna, Grosjean, Vergne, Kobayashi, Rosberg, Perez and Schumacher are in the knockout zone.
Q2Alonso goes fourth. That will see him into Q3 safely.
Q2Button comes into the pit for a minor repair, but he'll need to get back out there as he is in a precarious position in 10th. On the cusp...
Q2There's an electrical failure on Button's car and he's out!
Q2Vettel and Webber have gone fastest. Hamilton is in third.
Q2Senna just misses out on a place in the top 10! But he's also out along with Button.
DRIVERS OUT:Senna, Button, Di Resta, Vergne, Perez, Kobayashi, Rosberg
TOP 10 SHOOTOUT:Vettel, Webber, Massa, Hamilton, Grosjean, Maldonado, Hulkenberg, Schumacher, Alonso, Raikkonen
6.47pmJenson Button: "It's a problem with the throttle. There's no power. Hopefully it's something we can get sorted for next year."
6.49pmButton hasn't been very impressed with the McLaren machine this year. It has let him down on a few occasions, as it has with Hamilton.
Q3Schumacher is first out of the traps in Q3.
Q3Grosjean is currently the fastest man on the track, but with 1.36. Vettel went 1.35 in Q2 so don't expect that time to hold up.
Q3And there goes Webber, taking top spot with 1.36. Red Bulls have so much pace around this circuit.
Q3Hamilton now snatches provisional pole.
Q3Vettel looks like he's about to usurp him. Quick first two sectors...
Q3And there you go, Vettel takes pole with 1.35. That'll take some beating.
Q3Alonso is down in 7th and needs to get something close to Vettel and Hamilton.
Q3Hulkenberg goes 6th, pushing Alonso further down. Hamilton consolidates second with a time just a couple of hundreths slower than Vettel. Great pace!
Q3Alonso can only manage 7th!
Q3Vettel improves his time but Hamilton looks quick....
Q3He just misses out by a tenth of a second! So very close from Hamilton! Superb driving!
7.06pmRomain Grosjean has a five-place grid penalty so that should give Alonso an extra place, but he was bumped down to 9th and has a mountain to climb...
FINAL GRID POSITIONS:Vettel, Hamilton, Webber, Raikkonen, Schumacher, Massa, Hulkenberg, Alonso, Grosjean, Maldonado, Senna, Button, Di Resta, Vergne, Perez, Kobayashi, Rosberg, Ricciardo, Glock, Pic, Petrov, Kovalainen, De la Rosa, Karthikeyan
