Mike Lorenzo-Vera holds a three-shot lead in the DP World Tour Championship, while Tommy Fleetwood and Jon Rahm boosted their chances of winning the Race to Dubai title on Friday.
Lorenzo-Vera started the day with a one-shot lead ahead of Rory McIlroy after signing for an opening 63 - the lowest first round in the history of the tournament.
The Frenchman led by a mammoth seven shots on the back nine at Jumeirah Golf Estates, but his advantage over Fleetwood and Rahm was reduced to three when he bogeyed the last hole.
Lorenzo-Vera, bidding to win a first European Tour title in what is the last event of the season, is 12 under after signing for a three-under 69 on the Earth Course.
The world number 96 started with back-to-back birdies and hit the turn in 33 after further gains at the seventh and eighth holes, but a second dropped shot of his round at 15 and another at 18 mean he is not sitting quite so pretty.
Fleetwood carded a four-under 68 and is course to be crowned European number one for a second time, a seventh birdie of the day at the final hole also enhancing his prospects of winning back-to-back titles.
The Englishman, who claimed the Nedbank Golf Challenge title last weekend, was seven adrift of Lorenzo-Vera when the leader chipped for a birdie at 14, but is well poised in a share of second place with Rahm.
Rahm sunk a putt from around 12 feet for an eagle-three at 18, recovering well on the back nine after a double-bogey at the eighth.
The Spaniard and Fleetwood both know they can be crowned Race to Dubai champion if they finish solo second, provided Bernd Wiesberger fails to shoot up the leaderboard.
Austrian Wiesberger started the season finale as the man to catch and will be guaranteed to fend off the rivals chasing him down if he finishes outright second, but is joint-13th following a 71.
Shane Lowry and Matt Fitzpatrick, the other two contenders to win the Race to Dubai, are in a share of 13th and 17th respectively.
McIlroy is six shots off the lead after a disappointing 74, while Tom Lewis sits five behind Lorenzo-Vera on seven under.