Matteo Manassero took the trophy after burying a 12-foot eagle putt during a tense final-round play-off on the demanding Serapong course.
The 19-year-old saw off the challenge from world number 10 Louis Oosthuizen to secure the championship – his third win of the season and one that netted him US$1m in the process.
The event went to a playoff after both players finished the final round on 13 under par.
“The challenges of the Serapong course brought out the best in all golfers during the games,” said Robert Morrice, Chairman and Chief Executive of Barclays, Asia Pacific.
He added: “The tournament hosted over 2,200 clients and colleagues, and provided Barclays with a great opportunity to profile our brand across the region and around the world.”
World number one Rory McIlroy finished the tournament with a flourish, holing a 35-foot downhill putt for an eagle to claim third place, and clinch the European Tour’s Race to Dubai.
As well as sponsoring The Singapore Open, Barclays also sponsors world top-10 player and former Masters champion Phil Mickelson, and is the title sponsor for The Barclays tournament in the USA.