American Pat Perez fired a 66 to grab fourth on 203 with four-time major victor McIlroy in fifth on 204 after a 68 on a course where he has won twice and set a course record of 62 then broke it with a 61.
Dufner stumbled back with bogeys on 11 and 12 after missing each fairway but answered with birdies at the 14th and par-5 15th, blasting from greenside rough and a bunker within two feet of the cup on each to hang onto a share of the lead.
But McIlroy pulled it together, making birdie on the short par-4 14th hole and the reachable par-5 15th hole to claw back to within two shots of the leaders, none of whom could separate themselves from the pack coming down the stretch at Quail Hollow's hard three closing holes called the Green Mile.
When the horn sounded for a weather delay, McIlroy had spiralled into a tie for 12th and found himself eight behind leader Homa. "I turned a 66 into a 70", McIlroy said.
But while the Helsinki native (38) edged ahead with a birdie four, Hebert drove the green at the short, par-four 18th and two-putted for a 69 to force a playoff on 20-under par.
But they had enough of a cushion to start the day to fend off the likes of Pat Perez, who shot a 5-under 66 and is a stroke back at 10-under. He finished off the tournament off by knocking in a 9-foot putt for par.
McIlroy was paired with Homa in Saturday's third round and said he came away "very impressed".
Englishman Justin Rose (68) was another shot back in third.More news: Apple offsets 17% drop in iPhone sales with services, wearables growth
"I didn't beat myself today", said Dahmen, who could hardly have been happier for the victor and was looking forward to a big night on the town. "It will be a good challenge to see where I'm at, what I'm doing". "I don't really get too down on myself. I'm usually good with words, but I don't think I have any". Check in for highlights from every tournament plus player interviews, player profiles, tournament previews, swing analysis and all the greatest shots and incredible moments. "I'm searching for things that are going to make me a better player".
But they got the full round in, so all the golfers will start at the first hole Sunday with just one round to play.
"I've played some great golf on this back nine and hopefully I can do it again", McIlroy said.
The PGA Tour is now just one event away from the second major of the year, The PGA Championship at Bethpage State Park in NY beginning on May 16th.
Garcia had one of the more colourful scorecards out of the top finishers.
Paul Casey made 15 pars and still managed to make up five shots on the lead, courtesy of a pair of eagles and one birdie. He's tied for seventh with Seamus Power at 7-under for the tournament and four behind the leaders.
The best round of the day belonged to Sergio Garcia, who fired a 65 to get to six under and a tie for ninth.
Rory McIlroy says that he has found the greens at Quail Hollow Club the most challenging this week due to the firmness and trickiness in play.