The 24-year-old from Florida has collected four top-10 finishes on the European Tour this season, including a tie for fourth behind German winner Martin Kaymer at the U.
S. Open in North Carolina in June.
Koepka again put himself in a good position to launch a final-day title challenge when he signed for a two-under-par 70 in a soggy third round of the $7 million Turkish Airlines Open.
That left him two strokes adrift of pacesetting Australian Wade Ormsby and one behind former world number one Lee Westwood, European Ryder Cup talisman Ian Poulter and pony-tailed German Marcel Siem.
“It would be nice to finally get a win,” Koepka told Reuters in an interview on a cold and rainy day during which the spectacular Taurus Mountains were hidden by a fog of grey mist that fell on southern Turkey.
“I’ve been cracking on the door for a while but I’ve learned a lot from some of my failures.
“I’ve been in the lead with nine holes to go and with five holes to go. I feel like in the last two months I’ve been ready to win and it would be disappointing to finish the year without a victory.”
Koepka was a long way short of his best on Saturday. He toiled with his close-range putting and was fortunate to limit the damage after smashing a couple of wayward drives.
“It was nice to finish with a 20-foot birdie putt at the last hole, it will make dinner taste a little better tonight,” smiled the world number 61 after ending up with a 10-under-par tally of 206.
“I missed a couple of short ones today. I was fine with anything outside of four feet but inside that I just felt I couldn’t make them.
“I was never comfortable over them and that was quite frustrating. It never felt right,” added Koepka who won three times on the second-tier European Challenge Tour last season to earn promotion to the main circuit.
“It’s all about how I’m setting up, the way the putter sits in my hands, the way it’s running up my right forearm. I’ll work on that in the next hour or so to try and put it right.”
Lady luck smiled on Koepka when he hit two wild tee shots on the front nine.
“On the first hole my drive went right into the trees,” he explained. “They only found it after the five-minute rule, I hit a provisional ball and went on to make a bogey.
“Then it was kind of funny at the seventh because my drive went left, finished up against a bush and my provisional there landed up against the lip of a bunker. I was happy to get away with just a bogey,” said Koepka.
“I made mistakes but I got away with them, minimised the damage.
“Overall it was disappointing because today I felt you could really score well. I felt the course was gettable and I could easily have shot six or seven under.”
(Editing by Rex Gowar)