The 33-year-old’s win was his first in America in five years and only his second worldwide since the 2006 Honda Classic. 

The tipping point came with a birdie on the par-three 16th, although Donald was already three up after five and had not trailed in any of his matches all week. 

He birdied the 11th, 12th and 15th in order to offset Kaymer who had managed to draw level at half  way.

The pressure of Kaymer’s parred sixth, birdied eighth, and 476-yard ninth with a bogey five may have got to Donald as he played a seven on the ninth. 

Donald, who moves to number three in the world rankings, managed to save a poor approach shot to the tenth, which landed him in the scrub, by wedging out and holing a par putt to match his opponent. 

A birdie on the 11th allowed Donald to edge one up which was doubled when Kaymer failed to get up and down at the next. 

From here on in the all-European final was easily Donald’s as Kaymer missed a three-footer at the 15th.

Kaymer’s condolence prize however, was to become world number one, knocking Lee Westwood into second and Tiger Woods into fifth. 

“I have not won in America for five years. It has been a lot of sweat and tears to get this to this point. It feels great. Hats off to Martin for reaching world number one – that’s quite an accomplishment, and makes this win a lot sweeter,” Donald said.

Donald added it was nice to see his hard work over the last five years paying off. 

He said: “You always have doubts and the wheels were coming off a bit, so the up-and-down on the tenth was huge and to have three birdies in the last six holes was special.

“Hopefully it will open the gates. I'm not a modern-day player because I don't hit it that far and that makes it harder for me, but this is great win and I hope there are more to come.”

The victory also earns Donald $1.4million and Kaymer, who was hoping to make it five wins out of his last 11 starts, will have to be happy with his place in history.

At 26 he is the youngest golfer to occupy the top spot after 21-year-old Woods did so first in 1997.  

Kaymer follows his compatriot Bernhard Langer and other European greats including Seve Ballesteros, Ian Woosnam, Sir Nick Faldo and Westwood at the top of the table.