Gary Stal overturned an eight shot deficit to deny Martin Kaymer and claim a maiden European Tour title at the Abu Dhabi HSBC Golf Championship.
The two-time Challenge Tour winner closed with a brilliant seven under par 65 for a 19 under total, which proved just enough on an exhilarating final day.
“It's really crazy and I’m very happy to win this tournament,” said Stal, whose final-day comeback equalled the largest on the 2014 Race to Dubai.
“This morning, I was thinking about second place, I didn't think about first place.”
Three-time winner Kaymer had carried a six shot lead going into Sunday's final round, and at one stage extended his advantage to ten shots after birdies at three of his first four holes.
Frenchman Stal started the day eight behind, but went to the turn in 32 and birdied the tenth just as two-time Major Champion Kaymer was beginning to falter.
The German double bogeyed the ninth after finding the desert scrub, and after Stal picked up another shot from 15 feet at the 11th the gap was down to two.
Kaymer found more trouble in desert down the left of the 13th, and ran up a triple bogey seven after duffing a pitch from the fairway to slip one behind.
Stal then holed from 20 feet at the 16th for birdie, and neither Kaymer nor World Number One Rory McIlroy could stop the 22 year old over the closing holes.
McIlroy almost holed from the sand at the last to force a play-off, but the four-time Major winner instead had to settle for a fourth runner-up finish in the event on 18 under, with Kaymer a shot further back in third following a round of 75.
“My dad and my mother, they made it possible to be a good golfer, and I just applicate my sport every day,” added Stal.
“I thought about all the people that were looking at me. I thought about my mother, Christine, who died in May while I was playing Wentworth - she passed away while I was playing, and I thought about her a lot, obviously.
“When I saw my name on the leaderboard, I started thinking, well, don't get excited, but I'm very happy obviously. It's an incredible feeling.
“For the four days, my attitude has stayed the same. I've told myself at the beginning of the tournament that I wouldn't get upset, and it paid off. I thought if I could putt well, if I could play shot by shot, it would pay dividends. Therefore, I just kept the same way, the same attitude.”
Kaymer admitted to being somewhat shell-shocked, but believes his general performance this week may bode well for the rest of the year.
“I don't really know how to put it into words,” he said. “It was very, very surprising today.
“I started off well and hit a couple bad tee shots and cost me double-bogey and a triple-bogey.
“Twice I missed the grass and I was in a bush – I had to drop it in the sand.
“I missed a lot of putts today, and therefore, was very difficult for me to make birdies.
“The positive is I was playing really good golf. That was nice after such a long break, when you play the first three days, I played so solid, missed barely a fairway. And today was a little bit different, but there's still a lot of positive, and that's tough to say after that round.”
McIlroy, who struggled with the putter in his third round 73, made his move with a hat-trick of birdies around the turn after enlisting caddie JP Fitzgerald’s help on the greens.
“Once I started getting JP to read putts, it was a lot better,” said McIlroy after a round of 66.
“I started off pretty slowly again and then we just sort of figured out we would try and read them together, and it helped.
“It was nice to finally get it going, but just that little stretch yesterday and then early on today sort of cost me the tournament.”