Jamie Donaldson was closing in on a second European Tour title at the Abu Dhabi HSBC Golf Championship, but the Welshman still had to hold off the challenge of Justin Rose over the closing holes.
The Welshman, who ended his long wait for a maiden victory at the Irish Open last year, carded five birdies and no dropped shots over the first 16 holes of his final round to reach 15 under par.
That was one ahead of World Number Five Rose, who was two under on the day with three to play after a day packed with twists and turns,
For a long time it looked like David Howell would end his seven-year wait for a fifth European Tour title as he overhauled long-time leader Rose.
The former Ryder Cup player, who less than three years ago stood 569th in the Official World Golf Ranking, caught the 32 year old with four birdies in an outward 32, then went ahead with another gain at the long tenth.
Rose had birdied the second, but went from left rough to right rough on the fifth and could not get up and down to save par, eventually turning in a level par 36.
Without a win since the 2006 BMW PGA Championship at Wentworth, Howell wanted to keep the pressure on those behind him but missed the green at the short 12th and bogeyed.
Donaldson birdied the 11th and Rose the tenth, but the latter made a mess of the next, going from sand to rough and hitting his chip far too strongly, for a bogey that gave Donaldson the lead on his own for the first time.
Howell's bogey was bad, but what came on the 414 yard next was far worse and almost certainly killed off his title hopes.
He thought he had hit a good second, but it landed short of the green in a bunker and after splashing out well to four feet he amazingly four-putted from there for a triple bogey seven.
At the same time Rose holed from ten feet at the 12th to rejoin Donaldson on 13 under, two in front of Olesen and Santos.
Donaldson suddenly became the man to beat when he rolled in putts of 18 and 15 feet at the 14th and 15th, but a five footer from Rose on the 14th narrowed the gap back to one in what looked like a duel between the two of them.
Donaldson parred the difficult 17th - he needed two woods to make the green - and was two ahead again after Rose carved his approach to the 16th and almost went in the water.
He chipped on to 12 feet, but missed the par putt.