Brooks Koepka joked that caddie Ricky Elliott guided him on all 68 of his shots to start The Open Championship at Royal Portrush.

As a Portrush native, Elliott knows the links course as well as anybody involved in the tournament this week.

And his local knowledge certainly came in handy for four-time major winner Koepka, who began his tournament with a three-under-par 68 to sit two back of leader J.B. Holmes.

Asked how many shots Elliott guided him on during his press conference, Koepka drew laughter from the media by replying: "68 of them."

Koepka said nothing his caddie has mentioned to him this week has come as a surprise.

"It's easy when he's just standing on the tee telling you to hit it in this spot and I just listen to him," he added. 

"I don't have to think much. I don't have to do anything. I figure out where the miss is and where I'm trying to put it and then go from there."

Koepka was among the later starters and was treated to heavy showers in between clear skies.

"I probably got poured on 10 times. Sometimes they'd come a minute, minute and a half and then other times - standing on the second tee box, man, I felt like the world was going to end," he said.

"Everybody else has got to deal with it. You just push on and see where I'm at and throw the rain gear on and hide under the umbrella a little bit, and when it's my turn, I'll just go out and hit one."