Luke Donald looked on course to capture The Race to Dubai as Rory McIlroy endured a difficult start to his third round at the Dubai World Championship presented by DP World.
While Donald burst from joint 12th overnight into a tie for third place after going to the turn in 32, his one remaining Race to Dubai challenger fell from third to 19th.
A bogey on the third was bad enough for the 22 year old US Open Champion, who had to win just to have a chance of denying Donald a double of money list titles on both sides of the Atlantic.
But then came a double-bogey seven on the long seventh, where the Northern Irishman, told the virus he has been struggling with may be Dengue fever, hit his second left into a bush.
After taking a penalty drop, he left his chip short of the green and needed three more shots.
He was down from seven under par at halfway to four under at the same time as Donald burst from four under to eight under.
The World Number One will complete an unprecedented double if he finishes in the top nine, regardless of what McIlroy does, but he was rounding off his year's work in style.
Spain's Alvaro Quiros was heading for tournament victory, however.
He recovered from a shaky start of his own to birdie the sixth and then eagle the 572 yard seventh.
That put him 14 under and five clear of Swede Peter Hanson.
The European Tour's biggest hitter started by straying into the bushes right of the first and did well to limit the damage to a bogey after taking a penalty drop.
He then birdied the second from 15 feet, three-putted the fourth, but made a second birdie from ten feet on the short sixth and was even closer in two on the next.
Donald shared third with his former World Cup-winning partner Paul Casey, and also German Martin Kaymer, who had the third course record-equalling 64 of the week thanks to sinking a bunker shot for eagle on the last.
Donald moved into a tie for second four behind Quiros when he added birdies on the 15th and 16th, first chipping to two feet and then hitting his approach to six feet.
McIlroy had back-to-back birdies as well on the 11th and 12th to repair some of the earlier damage, but a six footer for a third in a row eluded him and at six under he was tied for 13th.
Quiros was 15 under after a birdie on the 15th and Oosthuizen 11 under, but with a 66 for ten under Donald had made the move he was looking for.
He refused to consider The Race to Dubai a done deal, though, with McIlroy collecting another birdie on the 16th to stand seven under and joint 12th.
