Rock band Rage Against the Machine have won the most competitive battle in years for the Christmas number one.
The band's single, Killing In The Name, sold 500,000 downloads beating X Factor winner Joe McElderry's The Climb by 50,000 copies to clinch the top spot.
Their success followed a Facebook campaign designed to prevent another X Factor number one.
One retailer said it was a "truly remarkable outcome - possibly the greatest chart upset ever".
Speaking on the Radio 1 chart show, Zack de la Rocha from Rage said: "We are very, very ecstatic about being number one."
He added it was an "incredible organic grassroots campaign".
"It says more about the spontaneous action taken by young people throughout the UK to topple this very sterile pop monopoly," he said.
McElderry, 18, praised the campaign, adding: "It's been exciting to be part of a much-hyped battle and they definitely deserve congratulations."
Thanking all the fans who bought his single, he said: "This time last year I never thought for one minute that I'd win The X Factor, never mind about having a debut single out, so I'm just delighted to be in the charts.
"It's been such an incredible couple of months and I got the best Christmas gift I could ever have asked for in winning The X Factor."
He later told BBC Radio One he did not believe the internet campaign was a personal attack.
He said: "It's more against the show than me and I think if any other person had have won, the same thing would have happened, because the petition was going on before the winner had been announced."
Despite earlier in the week calling the campaign "stupid", X Factor judge Simon Cowell offered his congratulations to the couple behind it, Jon and Tracy Morter.
He said: "I am gutted for Joe because a number one single meant a lot to him but I have to congratulate Jon and Tracy, who started the Facebook campaign.
"I called Jon on Saturday to congratulate the two of them that, win or lose, they turned this into a very exciting race for the Christmas number one.
"I am proud of Joe - he worked really hard this week, but he has a great year ahead of him."
This is not the first campaign the Morters have launched to try to influence the charts - last year they attempted to get Rick Astley to the top spot.
Mr Morter, 35, said he learnt "how the charts work" from that experience, and "what you can get away with".
"When this year came around I just thought, let's have another go. If anything, last year was fun. This year it has gone stratospheric."
His wife Tracy said: "It was one of those little silly ideas that make you laugh in your own house.
"We really love music and remember when were were young the charts were really exciting. We just thought, wouldn't it be funny if that song got to number one?
"It took something really strong and forceful to get people behind it."
The Los Angeles rock band's hit also set another record: it has achieved the biggest download sales total in a first week ever in the UK charts.
McElderry's song was only released digitally after his victory in the X Factor, giving it less time to rack up sales than Rage Against The Machine.
On Friday the band's lead was just 9,000 copies, but sales then soared by 200,000 to secure victory.
Rage Against The Machine are signed to Epic Records, which is part of Sony Music, the same label as McElderry.
De la Rocha said the band would perform a free concert in the UK in 2010 to celebrate their chart win.
The past four Christmas number ones have all been by X Factor winners; Alexandra Burke's version of Hallelujah last year was one of the biggest selling festive singles ever.
Guitarist Tom Morello said it had "tapped into the silent majority of the people in the UK who are tired of being spoon-fed one schmaltzy ballad after another".
He added that proceeds from the single would go to homeless charity Shelter tying in with the Morters' Facebook campaign which includes an online link to give to the charity, raising over £70,000 so far.
The last big Christmas battle on a similar scale was between the Spice Girls' Goodbye and South Park character Chef's Chocolate Salty Balls in 1998. The Spice Girls won with 380,000 to their rival's 375,000.
Despite losing out on the single top spot, Cowell kept a hold on the album chart, with Susan Boyle's I Dreamed A Dream remaining at number one for a fourth week.