Donald shot 1-under-par 70 on Saturday to take a one-stroke leader over defending champion Jim Furyk (69 on Saturday) after three rounds at Harbour Town Golf Links. A victory would vault the third-ranked Donald to No. 1.
"I think there's a bunch of people behind us that have a good chance, too, so I don't count anyone else out," Donald said. "It should be a good battle out there."
There were seven of the world's top 20 players here this week, a field strong enough to push Donald past the idle No. 1 Martin Kaymer and No. 2 Lee Westwood.
Brendon de Jonge (66) and Scott Verplank (67) were two shots behind Donald at 9-under.
ASIAN TOUR: In Jakarta, Indonesia, Lee Westwood took a five-stroke lead after the third round of the Indonesian Master, shooting a second consecutive 6-under-par 66 despite a bogey on the last hole.
Westwood can reclaim the No. 1 ranking from Kaymer with a victory if Donald fails to win today at The Heritage.
Thitiphun Chuayprakong and Park Hyun-bin were tied for second.
CHAMPIONS TOUR: In Savannah, Ga., Wayne Levi and Keith Fergus shot 12-under-par 60 in better-ball play for a share of the second-round lead with Peter Senior and Sandy Lyle at the Liberty Mutual Legends of Golf.
Senior and Lyle combined for 61 that left them even with Levi and Fergus at 20-under 124 in the Champions Tour event at The Club at Savannah Harbor.
Kenny Perry and Scott Hoch shot 62 and were a stroke behind in a tie with first-round co-leaders Tom Kite and Gil Morgan, who had 63.
Augusta native Larry Mize and partner Hal Sutton shot 64 and are tied for ninth place, three shots off the lead.
Former Augustan Allen Doyle, who is teaming with Bruce Vaughan, combined for 65. They are tied for 16th place and are six off the lead.
The team of John Cook and Joey Sindelar withdrew because Sindelar has a bad back.
EUROPEAN TOUR: In Chengdu, China, Nicolas Colsaerts eagled the first hole and went on to shoot 6-under 66 to take a one-shot lead after the third round at the China Open. He's at 18-under 198.
Han Chang-won is one stroke back after 65.
Peter Lawrie and Gregory Havret both shot 68 to sit another shot back in a tie for third,
Former Augusta State golfer Oliver Wilson had 76 and is at 210, 12 off the lead.