PORTRUSH, Northern Ireland — The best week of Shane Lowry’s life began with his mind cluttered with uncertainty.

Lifting the Claret Jug on Sunday evening to the ear-splitting roar of the masses huddled around the 18th green at Royal Portrush was far, far away from Lowry’s mind. It wasn’t even realistic.

Lowry’s practice sessions in advance of the tournament were uneven, causing for some alarm for a player who’d missed the cut at the previous four Open Championships.

His uneasiness led to Lowry calling on his coach, Neil Manchip, for a session that had a lot more to do about talking things out than it did working on his swing mechanics at the practice range.

“I don’t feel like practice went unbelievably well this week,’’ Lowry told Manchip. “I felt a little bit uncomfortable.”

So Lowry and his coach/savior took a ride over to the Bushmills Inn, a stately old inn and restaurant that is a part of the Bushmills Whiskey empire here about a 10-minute drive from Portrush, and found a secluded place to talk things out.

“We just put everything out in the open, everything out on the table [about] what could happen [this week], what might happen,’’ Lowry said.

“I left that room full of confidence and ready to go.’’

Lowry shot a 4-under 67 the next day in the opening round to immediately put himself in position to do what he did Sunday, which is the greatest thing he’s ever accomplished in his life by winning the Open Championship.

“It was more about him wanting to be perfect with the way he was hitting the ball and putting, and we just discussed that it doesn’t need to be perfect,’’ Manchip said as he stood on the back of the 18th green watching Lowry celebrate with his family and the Claret Jug. “I told him he has the skill and just let it happen.’’

So he did.

“I was probably as nervous as I’ve been in quite a while on the first tee, almost ever, I’d say,’’ Lowry said after his opening round Thursday. “I just hope I’m nervous on Sunday afternoon out there.’’

At 1:47 in the afternoon Ireland time Sunday, Lowry was there on the first tee and the noise from the home crowd raised the hair on your neck and gave you goose bumps, even if you weren’t Irish.

“It’s right where you want to be,’’ Lowry had said. “And you have to tell yourself that when you’re there: Where would you rather be: Here or sitting at home watching on TV?’’

Lowry, of course, knew the answer to the question he was asking.

An enduring quality to the latest “Champion Golfer of the Year’’ is the fact he’s not afraid to ask for help. Lowry wears his vulnerability on his sleeve. He tells Manchip everything, even if it might at times be too much information.

After the electric 8-under 63 he shot Saturday to surge to the four-shot lead he took into Sunday, Lowry recalled one of those TMI moments he had with Manchip.

“I needed a caddie for me in Valderrama, years ago,” Lowry said, referring to him calling on Manchip at the last minute. “I had a chance to win the tournament playing the 17th. We got down and did the [yardage] number and I said to him, ‘I’m absolutely s–ting myself.’ I don’t know what he said, but he was like, ‘That’s kind of the way it is.’ I like to talk about things.’’

That’s why, unlike the usual robotic response you get from so many players who lie when they say things like they’re not thinking about the end result but instead about the “process,’’ Lowry offers no pretense.

Lowry said that Wednesday night talk with Manchip over coffee “changed a lot, because I was quite nervous and anxious.

“The last thing you want to do is come up here and miss the cut, and that was kind of in my mind,’’ he said. “I wanted to play at least four days, and wanted to put up a good show for myself being in home. So, yeah, [that talk] really settled me down.’’

Now they can forever talk about the experience of being British Open champion, and how a little bit of open and honest communication can erase doubt and open the gates to greatness.

“I felt very unconfident on the first tee, I’m not going to lie,” Lowry said, referring to the first of the 269 shots he struck this week. “But I hit a good tee shot and from there on I was off and running.’’

Right to the Claret Jug.