Shane Lowry benefited from a missed par putt on the 18th hole from Ross Fisher to win the Portugal Masters title, while Andrew Dodt finished as the leading Australian.
Lowry shot his best round of the week - a five-under 66 - at the Oceanico Victoria Golf Course in Vilamoura on Sunday, and was jubilant when Englishman Fisher's short putt for par lipped the cup on the final hole to secure the Irishman's second European Tour victory.
Fisher finished one stroke behind Lowry on 13 under overall, with New Zealand's Michael Campbell a further shot back in outright third after his final-round 68 saw him to his first top-10 finish on the Tour in four years.
Overnight leader Bernd Wiesberger dropped out of contention late in the day, with the Austrian bogeying his final two holes to finish with a two-over 73 for outright fourth place on 11 under.
England's Richard Finch was fifth on 10 under, ahead of a group of six players all level at eight under.
Danny Willett and Raphael Jacquelin both started the day on even par but rocketed into the top 10 with eight-under rounds of 63.
Wales' Jamie Donaldson, South African George Coetzee, Sweden's Henrik Stenson and Scot Stephen Gallacher also finished on eight under overall.
Tom Lewis, last year's winner, finished tied for 49th on three under.
Dodt finished the best of the Australians, with his final-round one-over 72 enough to see him to a share of 16th place, while 2010 champion Richard Green ended with a two-over 73 to be tied for 37th.
Matthew Zions also went two over in his final 18 holes to finish tied for 63rd place.