The 2008 champion started the day eight shots off the lead but made seven birdies in 11 holes to close the gap on Viktor Hovland.
He holed a 30 footer on the 15th and then drove the 16th and got down in two to share the lead but looked to have lost his chance as he missed the green at the 17th for a bogey and found rough off the tee at the par five last, forcing him to lay up.
But the former World Number One does not have two Major Championships for nothing, and he put his third to 13 feet and holed the putt to set the target at 17 under.
In the end, that left him two shots shy of Hovland and still searching for a first victory since winning the U.S. Open Championship in 2014.
But the home favourite now has a second and a third in each of the last two Races to Dubai, and he was delighted to feel the spark of being right in the mix once more.
"I knew once I started the day I needed something really low and then obviously the putter was fairly hot today, I made a lot of good putts," he said.
"The goal at the beginning of the week was to get to 20 under, that's usually the number that you need on that golf course.
"I was playing well all week, the putter was a little cold and today it was hot. I was very pleased to make that many birdies, they gave me a chance.
"For me, it was important on 18, those are the putts that... when you need to make them, that was a putt that I made - I haven't felt that in a long time.
"Those are the moments that you really need when you don't have the success that you wish for.
"Last week at the U.S. Open, the third round really gave me a lot of confidence. I don't know really what happened during that round but something felt that I'm swinging it really consistently now.
"I was always having one or two rounds during the tournament that knocked me out of having a chance to win so making those putts in the end - also on 15 and 16 - it feels good.
"I haven't putted that well in a really long time, I putt consistently okay but today I needed everything and I pretty much made everything."
Kaymer was this week named as a Vice Captain on Padraig Harrington's Ryder Cup team but the man who holed the putt that sealed the Miarcle at Medinah is not giving up on teeing it up at Whistling Straits.
"Of course I would like to participate as a player," he said. "It's a huge honour to be the Vice Captain but I would like to give everything I have until Wentworth, until it's over.
"If it's enough, I will take it as a massive, massive bonus, especially the way I have played the last two or three years.
"But if I am in great form and maybe if I can put myself in contention a few more times until then, then maybe Padraig has something to think about."