Ricky Elliott knew immediately that Brooks Koepka was something special, but admits he could never have imagined just how right he would be.

Elliott started caddying for Koepka at the 2013 US PGA Championship and the pair have worked together ever since, during which time Koepka has won four major titles and 25million US dollars in prize money on the PGA Tour and become world number one.

Koepka will head to Pebble Beach next month looking for a third consecutive US Open victory – a feat achieved just once in the tournament's history – by Scotland's Willie Anderson from 1903 to 1905.

And the 29-year-old American will then rely heavily on Elliott's local knowledge as the Open Championship is staged in his caddie's home town of Portrush for the first time since 1951.

"I've played there a lot growing up but Brooks hits the ball differently than the lines I hit it on," said Elliott, who is good friends with another Portrush native, former US Open champion Graeme McDowell.

"I'll have to work on my yardage book for Brooks playing it but obviously a little local knowledge doesn't hurt. Brooks has got a big following in Portrush, probably because of me, so he'll be well supported and I think Portrush will be set up well for him."

Elliott was a very good golfer in his own right, winning titles such as the Ulster Boys Championship and the Ulster Youth Championship as well as representing Ireland at the 1990 European Youths Championship.

After attending the University of Toledo on a golf scholarship, Elliott tried to make it as a professional before accepting an assistant professional's post at Lake Nona in Orlando.

The 42-year-old eventually moved into caddying and worked for the likes of 2003 Open champion Ben Curtis before the job opportunity which would change his life.

"Claude Harmon was coaching Brooks and he said he needs a caddie for Oak Hill," Elliott added. "We made the cut and then Claude said at the end of the week, 'do you fancy doing a few more?', and six years later... It's been all right.

"The first practice we played I just thought, 'This guy is the real deal, he is hitting the ball unbelievably.' There was just something about him. Obviously you could never say he was going to do this, but there was always something that was different about him."

Koepka won his first major in the 2017 US Open at Erin Hills and after becoming the first player since Curtis Strange in 1989 to defend the title at Shinnecock Hills, he also won the 2018 US PGA at Bellerive.

After finishing second to Tiger Woods in the Masters last month Koepka then led from start to finish at Bethpage and Elliott added: "What he's just done goes down in history.

"He's just so calm all the time. He obviously realises he's one of the better players out here now and getting through at Erin Hills sort of stamped that on him and his place in the game now is in stone. He's just one of the best players and to be honest he goes out there and thinks that.

"One of Brooks's qualities is that he listens to people around him; he takes advice, he likes to talk to other players, especially Graeme (McDowell) in the early days, finding out what it takes to win a major and have a successful career."

Elliott admits it was "embarrassing" to see Koepka's tee shot on the par-three 14th fly the green by 15 yards and his fourth bogey in succession meant his seven-shot lead was down to one.

At that point the raucous crowds were chanting their support for nearest challenger Dustin Johnson, but Johnson would bogey the 16th and 17th to give Koepka the breathing space he required.

"We just had to block it out and keep talking between ourselves," Elliott said of the chants. "I'm sure he heard it.

"Obviously the crowd came out the whole weekend thinking the event was over, people not knowing golf, and all of a sudden they had a game on their hands late in the fourth quarter so they are obviously going to be hoping for the underdogs.

"If you're 4-0 up and the other team scores three goals (people are) going to be hoping for them to score the equaliser. We could understand why they were hoping for DJ, they were probably sick of hearing Brooks's name all week."

Koepka himself felt the chants helped him refocus and there will be no chance of a repeat scenario at Portrush, where Elliott's connections will ensure both men have plenty of support.

"I'm excited to get over there," Koepka said. "That's one place I've never been, which is shocking, because I've been all over the world.

"It will be special for Ricky. It will be special for me. I'm sure he's going to have his family, his mom and dad will be out there. I think he's staying with them that week.

"I think everybody in Ireland has been waiting for this for a long time, so it will be very special."