Wearing a pink dress with diamante studs that had a giant cascade of frills slashed below the waist, the 22-year-old gasped and threw her hands to her face as she was declared the winner.
"I felt the most gorgeous woman in the world. I was so happy and I wanted to shout, to cry, to stand still and to smile. So many emotions," she told AFP.
"I'm incredibly happy for this moment, for this opportunity and for winning and I'm grateful with my life."
Sarcos, who was brought up in a nunnery after being orphaned aged eight, has a human resources degree and works for a broadcasting company.
Last year's Miss World, Alexandria Mills of the United States, took off her sparkling crown and placed it on her successor's head as Sarcos sat in a shimmering silver throne.
Miss Philippines, Gwendoline Ruais, was named the runner-up, while Miss Puerto Rico, Amanda Perez, came third in the contest, which was back in its home city to celebrate its 60th anniversary.
Some 113 beauty queens from Albania to Zimbabwe took their place on the stage at the Earls Court Two auditorium in west London, with the show being broadcast live to an estimated audience of more than one billion viewers in 150 countries.
Around 50 feminists rallied outside, waving placards reading "Objectification won't achieve world peace", "Being a woman is not a competition" and "Sexism is pretty ugly".
A handful were veterans of the infamous 1970 Miss World final protest, when stink bombs were hurled on stage during a noisy demonstration.
The thousands of fans inside -- many dressed to the nines -- cheered, waved flags and shouted for their favourites.
Several point-scoring rounds were held over the previous two weeks during the contestants' tour of Britain, with the results revealed on stage and the top 15 going through to the semi-finals.
While beauty remains central to the event, brains, skills and good causes also play a major role. The majority of this year's have degree-level education and can speak at least three languages.
Miss Venezuela topped the interview round; Miss Dominican Republic, Marianly Tejada Burgos, was named the sports champion; home favourite Miss England, Alize Lily Mounter, won beach beauty, the classic swimwear contest, while Miss Kazakhstan, Zhanna Zhumaliyeva, was named top model.
The crowd were played clips from the talent round -- where performers sang, danced and gave piano recitals -- won by Miss Chile, Gabriela Pulgar Luco.
Miss Ghana, Stephanie Karikari, and Miss Indonesia, Astrid Yunadi, were the joint winners of the beauty with a purpose category, where contestants can highlight a charity project.
With the scores collated, Miss Puerto Rico topped the leaderboard, ahead of Miss Venezuela, Miss Philippines, Miss Ukraine and Miss Scotland.
The final seven -- chosen by the judges, who included nine former Miss Worlds -- were Miss England, Miss Korea, Miss Philippines, Miss Puerto Rico, Miss Scotland, Miss South Africa and Miss Venezuela.
Just before the winner was announced, a message of support from former South African president Nelson Mandela was read out on stage by one of his grandsons, backing their work "empowering young people to be of service to their communities."
The contest's charitable programme, set up 40 years ago, has raised $800 million (580 million euros) to date.
Sarcos's victory means that Venezuela now tops the all-time leaderboard alone with six titles, pulling clear of India and the United Kingdom.
"Winning means everything to me and I hope to take advantage of being a winner in a productive manner," the 61st Miss World said.
"I first and foremost want to help people in need.
"I would like to help people like me. I am an orphan. I would also like to help the elderly and troubled teenagers. As many people as I can."
The pageant was first held for the 1951 Festival of Britain and was staged in London until 1989.
Former contestants include Oscar-winning US actress Halle Berry, a 1986 finalist, and 1994 winner Aishwarya Rai, the Indian movie star.
It was announced that the Miss World final will go straight back to China for 2012, this time to Ordos in Inner Mongolia.

source: yahoo