The German maintained his cool on the back nine, despite home favourite Charl Schwartzel drawing level with him as he reached the turn, securing the crystal globe trophy with a three-under-par 69 in the final round for an overall tally of eight-under-par 280.
Kaymer was the archetypal efficient German, mirroring the original golfing model, Bernhard Langer, who won the Champions Challenge for seniors on the previous day, also by two strokes.
Although the blue skies and searing heat usually associated with the Nedbank Golf Challenge gave way to steady rain on Sunday, Kaymer revelled in the conditions and said the final round had been the easiest.
“Today was the easiest of the four rounds, there wasn’t much wind, it was fairly calm and easier to hit the fairways. It was easy to be aggressive, you could hit mid-irons and the greens were holding, they stopped very quickly,” Kaymer said.
The Ryder Cup hero was relaxed and seemed to be enjoying himself as he set out for the final round with a one-stroke lead over Louis Oosthuizen.
A magnificent eagle on the par-five second hole was the perfect boost, but he immediately handed back the advantage with a double-bogey on the third, his pulled drive being unplayable.
Five straight pars followed before Kaymer successfully held off the charging Schwartzel with three successive birdies from the ninth hole.
But the 27-year-old, playing in the NGC for just the second time, made some bad mistakes on the back nine, but recovered from them in brilliant fashion.
He found a greenside bunker on the par-three 12th hole and then chipped 12 feet past the hole, but made the putt for par.
Then, on the par-five 14th, he sent his drive way left to where the sun don’t shine. Incredibly, his ball landed in a clearing in the thick Pilanesberg bush and Kaymer was able to rise to the challenge of hitting his ball back on to the fairway and then producing a superb third shot that landed 10 feet from the flag to set up the most unlikely of birdies.
“My tee shot on 14 was the biggest piece of luck, I was very lucky to find the ball and then it was in a perfect position just to chip out on to the fairway, which led to birdie,” Kaymer said.
The 2010 PGA champion did drop a stroke on the par-four 15th after hitting his approach shot over the green and then chipping 10 feet short of the flag, but he escaped from big trouble again on the par-three 16th, sinking a clutch 18-foot putt for par.
Kaymer had weathered the storm and two pars coming in completed a very impressive triumph.
Schwartzel played very well too on the final day, matching Kaymer’s 69 – in fact, he could easily have gone a couple shots lower were it not for a frustrating day with the putter, a few putts hanging agonisingly on the edge of the hole.
The auburn-haired Oosthuizen, who began the day hot on Kaymer’s heels, saw his challenge fade away as he mixed three birdies with five bogeys for a 74, finishing fourth on two-under-par overall.
It was Schwartzel, however, who had the most regrets, looking as glum as the weather, with not even a sunset over the Pilanesberg hills to cheer him up.
He birdied the second hole and then went on a hot streak around the turn with further birdies on the ninth and 10th holes. His chances looked bright as he birdied the 14th hole and Kaymer bogeyed 15 to narrow the gap to just one stroke.
But his hopes disappeared on the penultimate hole when he left his approach shot short on the par-four 17th and then duffed his chip for a costly bogey.
“It was really tough out there, the course played long. I gave it a good shot but was just short at the end. I’ve always liked this course but it just doesn’t seem to suit my eye, it’s always a real hard grind for me,” Schwartzel told CCTV after his round.
Langer, who Kaymer credited with being a great help during the Ryder Cup, was waiting at the final hole for his countryman as Germany celebrated a double triumph.
Langer also won the NGC twice, in 1985 and 1991, and was also the first German golfer to reach number one in the world rankings.
Kaymer became the second early last year and is eagerly trying to recapture that form.
His win at Sun City, beating some of the best golfers in Europe, is a step in the right direction and he will begin his 2013 campaign with confidence, keen to pick up where he left off at the Gary Player Country Club.
“I’m very happy that I’ve finally won this year. I’ve been practising hard and playing well, but it just didn’t happen for me before today. I said to my caddie, Craig Connelly, that we have to win once a year at least.
“Bernhard has been a very big help to me and everyone talking about a German double put a bit more pressure on me. But I’m very proud to now have my name on the path at the ninth green, joining that special circle of winners,” Kaymer said.
The focused German can fondly remember the weekend he played like a world number one at Sun City as he aims for the pinnacle of world golf again next year.