The six was Donaldson's only dropped shot of the day. He had resumed two behind Rose, but birdied the first, ninth and 11th and then, following Howell's horror show, sank putts of 18 and 15 feet on the 14th and 15th to go two ahead.
His 68 gave him a 14 under par total of 274, one better than his close friend Rock managed a year ago when he beat McIlroy by one and Woods by two.
As for that Masters invite photo being sent to Rock, Donaldson said: "It's just banter. He was ill in the week and said 'Get my trophy back'."
Holding it up he added: "Here you are Rocky!"
Rose had led from his opening 67, but managed only a closing 71. There were three back-nine birdies in that, but also bogeys at the 11th and 17th after he missed both greens.
Rose, whose runners-up finish was still good enough to take him back to fourth in the world, said: "It was definitely hard work today.
"For some reason it was hard to see the breaks on the front nine, but I pulled it together really well and felt I got into a really good competitive mode.
"When I birdied 14 I didn't realise Jamie had had a hot round. I had actually expected to be one ahead at that point and I was one behind, so every credit to Jamie.
"I didn't do a lot wrong. It's hard to beat yourself up about it.
"I felt like I brought my best stuff on the back nine rather than the front nine, so that's encouraging.
"I don't think I need to do anything different - just need to keep chipping away and keep swinging well.
"But was a long, hard week to end up finishing second."
As for his closing putt his mind went back to the Ryder Cup last September.
"It reminded me exactly of the putt at 18 against Phil (Mickelson), just outside right edge. That's exactly where I hit it and unfortunately this time the putt didn't go in for me.
"Would I swap it? No, I wouldn't!"
Nor would he deny Donaldson his triumph. He had "four years in the wilderness" after being told his injury trouble was a spinal condition called Pars Disease.
One doctor told him his career could be over, but he went for another opinion and instead of it being a nightmare the story since has been the stuff of dreams.
The 22 year old Olesen had held a share of the lead after birdies at the fourth and fifth, but a double bogey six at the next ultimately left him with too much to do.
“I was trying to go for the green but I knew the lie was bad and I tried anyway,” he said.
“Maybe I should have just laid up, but you can always say that after. I tried to make birdies today, and I didn't make that many unfortunately.”