Austin, Texas - Defending champion Lewis Hamilton secured his third world title in dramatic fashion on Sunday (Oct 25) when he took victory in a roller-coaster, stop-start, wet-and-dry 2015 United States GP.
The 30-year-old Briton, who started from second on the grid, came home 2.850 seconds clear of his Mercedes team mate Nico Rosberg to deliver his 10th victory of a dominant season.
Hamilton now has an unbeatable total of 327 points, moving him beyond the reach of both Rosberg, who finished second, and four-times champion Sebastian Vettel of Ferrari, who came home third.
But an emotional Hamilton owed his victory, in the end, to an unforced error by Rosberg on the 49th lap when he made a mistake and ran wide at Turn 15 as the pair duelled for the lead.
Read: 2015 US GP: Hamilton wins 3rd F1 title in Texas
"It's the greatest moment of my life," said Hamilton, on the verge of tears. "Thank you all so much, I am so grateful to you all. And to my family I love you all."
Dutch teenager Max Verstappen finished fourth for Toro Rosso ahead of Sergio Perez of Force India, Carlos Sainz in the second Toro Rosso, Jenson Button of McLaren and Pastor Maldonado who was eighth for Lotus.
Felipe Nasr came home ninth for Sauber and Australian Daniel Ricciardo was 10th for Red Bull, having passed two-times champion Fernando Alonso of McLaren on the final lap.
Hamilton's success enabled him to equal the record of Jackie Stewart as the only Britons to win three drivers' world titles and the first to win two championships in succession.
"I'm very disappointed," Rosberg told rock star Elton John who was carrying out the podium interviews at the Circuit of the Americas.
"Something like that (his late error) has never happened to me ever. Really tough to lose the lead and the win like that."
Vettel, who started from the middle of the grid after a 10-place penalty, added: "We have a great car. I think we have exceeded all expectations, but it doesn't feel great when you cross the line and you know you can't win the championship any more."
After a two-day deluge, the race began with a rare appearance by the sun, a drying breeze and all the drivers on intermediate tyres.
When the lights went out, pole-sitter Rosberg was out-started by Hamilton who drew level and then eased his team-mate wide to the right at the first turn to seize the lead and the initiative.
Rosberg fell to fifth in the early scraps as the Red Bulls rushed past to take second and third, Daniil Kvyat driving with real hunger and panache.
Hamilton fought to keep his car in front on cold tyres, but finished the first lap 1.4 seconds clear of the Russian with Rosberg fourth behind Ricciardo.
Behind the leaders, there were several skirmishes including a collision between the two Saubers, in the team's 400th Grand Prix entry, a puncture for Alonso after a collision with Massa and a fine attack by Vettel who rose from 13th to seventh.
Valtteri Bottas retired his Williams with a broken rear suspension.
The debris required a Virtual Safety Car clean-up which slowed and bunched the field and, on resumption, Rosberg passed Ricciardo and then did the same to Kvyat on the back straight to claim second.
The German was soon within a second of Hamilton, but unable to make an impression and by lap 11 the gap was back to 1.1 seconds.
By this stage, their tyres were graining severely in the tricky conditions.
Both Red Bulls were clearly easier to handle but lacked the power to match the Mercedes, or overtake, until Rosberg slewed wide at Turn One and Ricciardo pounced.
The Red Bull looked supreme in the conditions and was soon pressing Hamilton, whose rear tyres were providing little grip, before he swept into the lead on lap 15, promptly delivering a fastest lap and opening a lead of 2.7 seconds.
By lap 18, his lead was four seconds and Hamilton, on dead tyres, was sliding, losing a place to Rosberg, before he pitted on lap 19 to switch to slicks. It was one lap too soon.
Ricciardo followed one lap later, along with Kvyat and Rosberg, all three holding their advantage on Hamilton when they re-joined.
Rosberg took advantage of his new rubber to take the lead on lap 22 and was soon four seconds clear of Ricciardo with Hamilton up to third.
Win on a platter
The defending champion took second on lap 26 and began the chase after his team mate who was nearly 10 seconds ahead.
Hamilton closed to within half a second of Rosberg with a series of fastest laps.
Rosberg and both Red Bulls pitted under another Virtual Safety Car, but not Hamilton who inherited the lead ahead of Vettel and Verstappen.
Rosberg was soon up to second and closing down Hamilton when Kvyat crashed heavily to bring another Safety Car deployment.
Hamilton swiftly pitted and rejoined second behind Rosberg and ahead of Verstappen while Vettel also pitted again re-joining fourth.
On lap 49, the pressure told and Rosberg ran off line exiting Turn 16, gifting his team mate the lead once again and, with it, his third world championship.