There were plenty of raised eyebrows when Rory McIlroy hired his best mate Harry Diamond as his caddie – but it wasn't always the plan

The lazy thinking is that Harry Diamond is a mate of Rory McIlroy’s and it’s just a nice arrangement to have your best mate on the bag – McIlroy met Diamond on the putting green at Holywood when he was seven and Diamond was 12.

“I was an only child and Harry was a big brother. That’s sort of how it felt growing up — a big brother’s influence on a little brother. He was the one that introduced me to alcohol, the one that introduced me to girls,” McIlroy told the Irish Independent in an in-depth interview.

McIlroy even caddied for Diamond well before their roles were reversed. The pair had a win together at the Ulster Boys in 2002, while Diamond also won the West of Ireland, played for his country, and played in an Irish Open.

“That’s the back story that people don’t know,” McIlroy explained. “Harry was my best man. We’re very close. I love having him on the bag. I’m a different person. And I’m never going to give him shit even if something goes wrong. It would not be worth it.”

When McIlroy and JP Fitzgerald went their separate ways the week after the Birkdale Open in 2017, Diamond stepped in on a short-term basis. Two and a half years later, they’re still going strong.

The Rory-needs-a-proper-caddie chat is long gone as he goes back to World No. 1 and onwards to more majors.

“It was a temporary thing. The rib was still bothering me and I couldn’t keep going. I needed to fix it. I was going to play Akron, the PGA, the FedEx Cup, the British Masters, Dunhill and that was it.

“So I said, ‘Would you do these last few events for me?’ He said, ‘Love to.’ I think I was still in the top three in the world, and the first two days at Akron we’re playing with Jason Day and Jordan Spieth — so 1, 2, 3 in the world — and Harry’s like, ‘Jeez, you’re throwing me in at the deep end!'”

McIlroy finished 5th, then 22nd at the PGA, and the pair nearly got their first win together at the British Masters at Close House.

“After the Dunhill Erica and I went on a sort of second honeymoon,” McIlroy added. “We drove around Italy and the south of France and I had a bit of time to reflect. It was lovely. I came back and started to rehab and get myself healthy, and was very, very disciplined leading up to ’18.

“I was looking around but I wanted to keep Harry on the bag. A caddie to me has always been someone that you need to have a good relationship with. I had this great relationship with Harry but I didn’t know if he wanted to do it. He’s still involved in the running of his dad’s business and has a lot going on back here. It’s a nice life. He was doing well.

“The conversation was, ‘I know it was on a temporary basis but I’d love you to keep doing it. I think we can really achieve something.’ I wanted him to feel fully invested and part of the journey too.”

After close shaves in Abu Dhabi and Dubai McIlroy and Diamond had their first win together when a closing 64 at Bay Hill saw them tear the field apart.

“It was obviously great but the person I could not have been more happy for was Harry because he had only been on the bag a few months and was getting a lot of flak.”

Follow NCG on on Twitter, Facebook and Instagram.