A double bogey seven on the last hole then led Kaymer came close to doing the same thing in his bid to dethrone Lee Westwood as World Number One.
The 25 year old German probably has to win the Dubai World Championship presented by DP World for that, but his "very frustrating finish" has left him six strokes behind leader Ian Poulter.
Westwood is only three off the lead and Kaymer, whose approach to the 620 yard last rolled into the ditch, said of his challenge for the tournament: "I kicked myself out of it I think.
"I will play as aggressively as possible and I can't lose now. It looks like I have won The Race to Dubai, which was my goal.
"But it would be more satisfying if I shoot a low round - between 66 and 63, which I think is possible."
He was joint leader after starting the back nine with a hat-trick of birdies, but promptly bogeyed the next two before double bogeying the last.
McDowell, meanwhile, is ten shots back and down in 30th spot after a 69. He needs a third place finish just to have a chance of grabbing The Race to Dubai title.
"Barring the impossible Europe's Number One is not a reality for me any more," he stated.
"Martin is definitely going to do it unless I shoot 55, which unless one of you boys (a handful of reporters) putts for me isn't going to happen."
McDowell, down on two under, was disappointed he had not been able to sustain a better challenge to Kaymer in the final week of the race.
But he said that a season of incredible highs - the US Open Championship and The Ryder Cup, of course - has left him convinced he can go on to become World Number One.
"What I've learnt this season is that I'm good enough," he said.
"I know what room I have for improvement, but it was great to see that my best is good enough to compete.
"Two or three years ago the number one player in the world seemed untouchable, but I believe if I work hard enough the next few years I could be the best player in the world."
McDowell felt his chances ended when he three-putted the short fourth and then missed birdie chances on the next two greens.
"I was just waiting for the taxi to turn up and take me home at that point," he commented.
"The course has not shown me much love. It's not my cup of tea - it frustrated me last year and is continuing to frustrate me.
"Sometimes you've just got to wave the white flag. I tried my heart out and it just didn't happen, but I'll have a cold beer and look back on a great season."