Donald, coming off a Japan Golf Tour win at the Dunlop Phoenix last week, had all seven of his birdies in a 10-hole stretch and is just ahead of world No. 1-ranked Rory McIlroy, Gonzalo Fernandez-Castano and Marc Warren.
McIlroy made a late charge with five birdies on the second nine Thursday. He had three in a row over Nos. 14-16. All six of Fernandez-Castano's birdies came on the back nine of the Jumeirah Golf Estates as he finished with three straight birdies. Warren had seven birdies and a bogey at No. 13.
Donald opened with four pars but had birdies on three of the next four holes. He opened the second nine with birdies at 10 and 11. A 15-foot putt gave him a birdie at the 13th hole and he just missed an eagle attempt at the 626-yard, par-5 14th.
Swim Week Miami Beach 2014 [PHOTOS]