Donald dropped five strokes heading into the turn, but regained four of them on a flawless back nine that left him at 5-under 208. Manassero had two birdies and three bogeys in an erratic front nine before making nine straight pars to also shoot a 72.
"I knew the nature of this course. If I could just find a couple of birdies, get back in the mix, then I thought I might be all right," Donald said. "So I kind of had to dig pretty deep and find a few birdies out there. I think getting that one birdie is important, just to kind of right the ship.
Top-ranked Lee Westwood and Fabrizio Zanotti of Paraguay shot 69s and were two strokes back.
The second-ranked Donald needs to finish in front of Westwood to capture the No. 1 ranking.
"It will be disappointing if I don't win, but I'm going to have to play a lot better than I did today," Donald said. "It wasn't pretty, but I'm back in with a chance, a good chance."
Manassero had shared the lead with Donald and Alvaro Quiros entering the round and was alone on top of the leaderboard after Donald had double bogeys at Nos. 2 and 6 and Quiros dropped four strokes in four holes up to the turn.
"It was the toughest of the three days we played so far," Manassero said. "Being on top of the leaderboard with some tricky flags and tough weather, it made it really tough. So I'm happy with the way I played. I saved a few good pars down the stretch and that is going to help me tomorrow."
Quiros made his second double bogey of the round at No. 17 in a 76 that left him four strokes back in a tie for eighth.