PORTRUSH, Northern Ireland – Rory McIlroy was there for the most consequential moment of Shane Lowry’s career, kneeling greenside when his best friend secured the first win of a lifetime.

It came a decade before The 2019 Open Championship at Royal Portrush, long before the two would become major champions, Ryder Cup stalwarts and close confidants. Back in 2009, they were just a pair of burgeoning Irish great hopes, McIlroy from up north, in the hills of Holywood, Northern Ireland, and Lowry from middle-country in County Offaly, Ireland.

McIlroy was the more accomplished junior of the two, but Lowry was about to achieve something McIlroy never did: Win the Irish Open as an amateur. Amidst pouring rain at County Louth Golf Club, Lowry outlasted Robert Rock in a historic playoff, becoming just the sixth Irishman to win his national open and just the third amateur to win any DP World Tour event. Fans swarmed Lowry as he threw his arms in the air and looked to the sky. McIlroy and Lowry embraced amidst the crowd.

It was the beginning of the ascension of Lowry, then just a pudgy 22-year-old searching for a breakthrough, and the start of deeply intertwining careers of McIlroy and Lowry, who have realized all the hope and promise that so many across Ireland and Northern Ireland wished upon them those years ago.

McIlroy and Lowry’s relationship has only grown in the years since. They live down the road from one another in South Florida, with McIlroy estimating they see each other five times a week when they are both home. They play practice rounds weekly – with Lowry usually signing up for the tee time as a single so McIlroy can show up without warning, jump in and avoid the distraction that comes from being this era’s most watched golfer. The families’ kids are close. So are their wives. Lowry’s family waited beside the Augusta National clubhouse to congratulate McIlroy, much like McIlroy did for Lowry when they were both kids.

Yet for all the time they’ve spent together – both McIlroy and Lowry are searching for pieces of what the other has. Something they see the other possess freely and experience viscerally from close-up, but are unable to obtain for themselves.

The Open Championship’s return to Royal Portrush is emblematic of that, though it’s rooted in more than just the accolades they’d love to trade. Yes, McIlroy’s achieved almost everything in the game. Perhaps the only trophy that he doesn’t have and still desperately wants is the one Lowry has, an Open Championship at Royal Portrush.

“When I was looking at the calendar for 2025, this was the tournament that was circled,” McIlroy said Monday.

And yes, Lowry would love to win the career Grand Slam and grab just a bit of the staying power that McIlroy has amassed. But their search is far more intrinsic and personal. The two bring out the best in each other and also provide a window of improvement that both are striving to reach.

“There’s parts of both of us that make us a little better,” McIlroy said.

Footage of Shane Lowry’s Open Championship celebration is easily accessible and owned by many. As is the case when you jump around pubs across town after you win the claret jug. It doesn’t take much to find videos of Lowry singing on stage, trophy in one hand and beer in the other. Within days of the victory, a hometown parade was set up in County Offaly, the main street in the small town of Clara filled to the brim to get a glimpse of their hero bringing a piece of sporting legend back to their little town.

Lowry has never shied from celebration. He wears his emotions on his sleeve and when he wins, he’s there for the world to see. It isn’t cockiness or a craving for the spotlight; it’s a genuine, “Can you believe that just happened?” joy that Lowry wants to share with those around him.

McIlroy’s taken note, and in his own way, did the same after the Masters. McIlroy isn’t as public-facing, but his extended Augusta National hangover is partly Lowry’s doing.

“I think Shane is very good at having fun, and I need more of that in my life,” McIlroy said, so much so that it became one of his New Year’s resolutions.

McIlroy has taken more vacations this year, spent more intentional time with family, and yes, celebrated more. And he’s had more to celebrate, winning three times, including THE PLAYERS Championship and AT&T Pebble Beach Pro-Am, alongside the historic Masters victory.

Has it been detrimental to his golf? He’s admitted as much, but it’s been needed for his mind. Partly because of the breadth of his accomplishments and partly because he doesn’t take praise well, McIlroy has been quick to move on after big moments in his career. Pro golf, with its unrelenting schedule, incentivizes it. There’s always a new tournament to win and a new goal to set. After the Masters, McIlroy made a conscious choice to revel in the achievement.

“It's definitely a place that I strive to be in, to be as comfortable getting away from (golf) as (Lowry) is in a way and enjoying the fruits of your success and sharing that with your loved ones,” McIlroy said.

McIlroy’s admiration of Lowry extends further. Lowry’s free-wheeling nature is likely never something McIlroy can fully employ, but some compartmentalization can be learned.

“I’ve struggled with the balance of being the best golfer, trying to be the best husband or the best dad and sometimes I get overwhelmed and it can get all a bit too much for me. Then I see how Shane does it with a lot of ease and sometimes you have to focus on one or the other, and, you know, he’s really good at that,” McIlroy said during an interview on Netflix’s "Full Swing" last year. “I see him as a good role model for me in some ways. I can learn a lot from him in how he handles everything in his life.”

But it’s McIlroy’s intense drive that Lowry has found the most inspiring. McIlroy once told Lowry it had been years since his last day off. Lowry’s remained astounded at McIlroy’s work ethic.

“He's done everything there is to do in the game. He finished that in April,” Lowry said, “and his constant drive to get better every day is admirable.”

Not that Lowry doesn’t work hard. It takes a particular kind of competitive insanity to even sniff pro golf. It takes another level entirely to reach the heights McIlroy has reached. There’s a relentlessness that the greats carry. McIlroy has it. Lowry sees it up close, but he is still searching for it.

“Sometimes when everything is going really well, I get complacent,�� Lowry said. “Then all of a sudden, before I know it, I'm like 3-over through 5, and you start to have a panic because you feel like you're going to do well.”

In a way, they are the perfect pair. McIlroy, the maniacally driven mega-talent that can’t separate sport and life, and Lowry, the emotionally-charged but grounded star who can’t help but feel in every moment. Separately flawed, but complete together.

“I feel like I’m good for him,” Lowry said, “but he’s also really good for me.”