The world number two, who needs to finish eighth on his own to take over from Rory McIlroy at the top of the rankings, was at his scrambling best to return a three-under-par 69 for an 11-under 205 total as gusts up to 40-kph swirled around Wentworth.
"That was by far my best round of the week," Donald told reporters. "The course is not geared towards a bombing long-hitter, it's geared towards someone who can work the ball around.
"I went for a run at nine o'clock this morning and it was blowing then so I knew it was going to be tough today."
Fellow Briton Justin Rose claimed second spot on 207 after another 69, two ahead of Irishman Peter Lawrie (72).
Course designer Ernie Els was on the fringes of contention in joint fourth on 211 alongside fellow South Africans Branden Grace and Richard Sterne and 1999 British Open champion Paul Lawrie.
A scorching sun shone throughout the day at the European Tour's flagship event but only a handful of players managed to break par as the wind sent scores soaring.
Donald picked up three birdies in a flawless performance over the first 14 holes.
He dropped his first stroke of the day at the 15th and calamity beckoned two holes later when, using his bright white driver, he sent his tee shot wildly right into the trees.
Donald's rescue attempt merely succeeded in pushing the ball a few yards forward before a low third sent it scurrying under the branches.
The Englishman, though, has a masterful short game and he proved it once again by wedging the ball up to six feet and holing out for a five.
"Making my birdie putt at the 18th was hugely important for me," said Donald. "I hit a couple of loose shots coming down the stretch but I was very pleased the way I finished."
Rose said he was relishing the potential of a final-round confrontation with Donald.
"The crowds have been so supportive of all the players this week but especially the English lads," added the world number 10.
"It's great to play in front of them here at home and playing with Luke tomorrow is going to be a lot of fun."
Fun was not the word Els had in mind after plotting his way to a two-under 70.
The South African, who has a property on the estate and has masterminded a complete overhaul of the famous West Course in recent years, was in a foul mood after failing to get his long approach to stay on the putting surface at the par-five 18th.
In a tirade sprinkled with expletives, Els accused tour officials and greenkeeping staff of failing to sufficiently water the greens.
"I landed my second at the 18th probably five yards too far," said the former world number one. "How much money did we spend on the 18th? We built a dam there. Why the hell was the green not holding?
"My point is, you hit a driver and then a four-iron gets you in the middle of the green. What else must you do next? Must I be the greenkeeper here?
"I'm a player, I'm not even supposed to tell them. Put water on a damn golf course? Surely they should know that? I can't control the wind and (it seems) I can't control the greens staff either."
Tournament director David Garland denied the putting surfaces had not been watered enough.
"The greens have been hand watered every night after play," said Garland. "Because of the conditions some fairways were also watered and tees were moved forward on the 13th, 15th, 17th and 18th as they were playing into the strong east wind."
The conditions proved too much for James Morrison who began the day with a four-stroke lead. The little-known Briton made two eights on the front nine as he ballooned to an 81 for 213, three under.
Morrison retained his sense of humour, though, raising his hands in mock celebration and smiling broadly after rolling in a curling six-foot putt at the 15th for his only birdie.