The 29-year-old retained the Wanamaker Trophy to become the first player to win his first four majors inside two years and he is confident he has more to offer.
“Double digits, easy! I don’t see why I can’t get to double digits,” he told CNN Sport’s Don Riddell when asked how many majors he can win during his career.
“I got four now, I’m 29, and they say you don’t peak until you’re in your thirties. So, hopefully, I peak then.”
‘I wasn’t afraid’
The Floridan was in a league of his own for most of this year’s PGA Championship, going into the final day with a healthy lead of seven shots.
Despite a late surge from close friend Dustin Johnson, Koepka managed to hold his nerve to win with two shots to spare.
“I was up against the ropes, it wasn’t easy. It wasn’t fun,” he said, describing his mini-meltdown when he dropped four straight shots on the last day.
“I wasn’t afraid. I mean I always had a lead, so what’s there to be afraid of.”
If anything, the pressure made the win that bit sweeter.
Despite two US Open titles and a PGA Championship already to his name, Koepka struggled to contain a rare show of emotion on the 18th green.
“It was special. To see that putt drop it was absolutely incredible,” he said after clinching the win.
“The emotion I had was something I’ve never experienced as a golfer, something you don’t see very often, even with me.
“I’m emotionless, I can be stoic at times but that one meant more to me than I think people will ever know.”
The new Tiger?
Following his impressive display, Koepka’s name is now being mentioned in the same breath as greats such as Jack Nicklaus and Tiger Woods.
It’s a comparison that Koepka can scarcely believe, having watched his heroes dominate the sport while he was busy working his way through the ranks.
He now looks a fitting heir to Woods’ long-term throne having beaten the Masters champion by 17 shots after two rounds.
However, any chance of Koepka beating Woods’ record of 10 major trophies before the age of 30 has long past.
“If somebody had said that I’d be mentioned with any of those names, I’d have just laughed at you,” said Koepka.
“It’s very humbling. You see the appreciation that everybody has for those guys and what they’ve accomplished in their careers and how great their careers have been.
“To even put my name with theirs is incredible.”
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Getting credit he deserves
Despite setting numerous records, the American’s rise has gone somewhat under the radar with his domineering style perhaps not getting the credit it deserves.
Unlike the short bursts of success enjoyed by the likes of Rory McIlroy — whose four titles came in just over three years — Koepka’s previous three major wins have blended into the background, much like Koepka himself.
Often deadpan in interviews and steely faced out on the course, the American publicly admits to having a chip on his shoulder.
A muscle-bound Koepka only took up golf after a car accident ended his dreams of making it in baseball, basketball and other more athletic sports.
However, he is now keen to show the world who he really is.
“I’m still finding me. I’m trying to be who I truly am, I’m not trying to please anybody else anymore,” he said.
“I’m not trying to bite my tongue or sit back and just go about my business. I want to be me, I want to be who I truly am and I think you see a lot of who I am on the golf course.
“I viewed the media as an enemy and now I’m viewing it differently. Trying to use it as an outlet has been quite humbling, to say the least.”