Rory McIlroy and Brooks Koepka shake hands after the first round of the U.S. Open golf tournament(Credits: AP)

Rory McIlroy made his best ever start to a major after shaking hands with rival Brooks Koepka ahead of his US Open first round.

The Northern Irishman cancelled his pre-tournament press conference amid the chaos that has engulfed the sport following the controversial merger, announced last week, between the previously warring PGA, LIV and DP World Tours.

McIlroy was the most outspoken defender of the PGA Tour when players started defecting for LIV Golf a year ago. When the tour and the Saudi backers of LIV announced last week that they were ending hostilities and going into business together, McIlroy said he felt like ‘a sacrificial lamb’.

Koepka was never as outspoken about his move to LIV, but when he won the PGA Championship last month, he blew holes in the theory that all the LIV rebels went for the easy money because they didn’t have game anymore.

In the lead-in to the U.S. Open this week, Koepka said ‘I enjoy the chaos’ that was consuming golf. He has collected all five of his majors since McIlroy won his fourth and most recent in 2014, and Koepka considers his ability to block the outside noise as a major advantage.

Rickie Fowler and Xander Schauffele lead the way after the opening round of the US Open (Picture: Getty)

McIlroy was able, however, to put the furore that accompanied his pairing with Koepke to one side by racing to the turn in 30 with five birdies in his first eight holes before following a run of six pars with a birdie on the 124-yard 15th, where Matthieu Pavon and Sam Burns both made a hole-in-one.

However, the four-time major winner then dropped his only shot of the day on the 18th and did not speak to waiting reporters after being required to undertake a drug test.

McIroy’s impressive start was overshadowed, meanwhile, by Rickie Fowler and Xander Schauffele who equalled the lowest score in men’s major championship history with stunning rounds of 62.

More: Trending

Fowler amazingly held that distinction on his own for less than 30 minutes as Schauffele, playing two groups behind, carded eight birdies in a bogey-free 62 of his own.

At eight under par the American duo led by two shots from compatriot Wyndham Clark and former US Open champion Dustin Johnson, with Rory McIlroy and Brian Harman on five under.

World number one Scottie Scheffler and Bryson DeChambeau were two strokes further back, while a frustrated Jon Rahm threatened to break a club over his knee as he struggled off the tee, but still managed to post.

MORE : PGA merger with LIV may cause Rory McIlroy to lose Canadian Open focus

MORE : ‘Money talks’ – Rory McIlroy defends the PGA Tour’s shock merger with LIV Golf

For more stories like this, check our sport page.

Follow Metro Sport for the latest news on Facebook, Twitter and Instagram.

All eyes were on the two rivals but Rickie Fowler and Xander Schauffele.