Collin Morikawa hit the front after round two of the 122nd US Open, but he has the world’s top three players chasing him down at Brookline.

Defending champion Jon Rahm and world number three Rory McIlroy are just a shot behind, with top ranked Scottie Scheffler one further back.

Matt Fitzpatrick leads the English challenge on two under after a 70.

The United States Golf Association may have feared the worst when questions about the fledgling LIV Golf series dominated the build-up, but they could not have wished for a better leaderboard at the halfway stage.

It’s the dream scenario for a major championship with four of the top seven in the world rankings battling it out for the title – led by reigning Open champion Morikawa looking to win his third major.

Four-time major champion McIlroy, who won last week’s Canadian Open, is in hot pursuit with world number two Rahm, and current Masters champion Scheffler.

There’s a sprinkling of surprise on a congested leaderboard, with world number 130 Dahmen in a tie for the lead in his third US Open, and fellow qualifiers Hayden Buckley on four under and Nick Hardy three under.

Rory rescues his round after double bogey

McIlroy was in trouble early on in his round after a wild shot from the fairway landed him deep in some Brookline fescue, and it took him three swipes to escape.

The response was emphatic though as he drained a 22-foot putt to escape with a double-bogey six when it could have been so much worse.

“It was massive,” McIlroy told Sky Sports of his putt.

“There aren’t many double bogeys when you’d have a little fist pump, but it was important to hole that and I came back really well after it.”

The McIlroy of recent majors may well have crumbled but there’s a steely calm and composure about the Northern Irishman this week, as he showed with three birdies in his final six holes to finish with a battling round of 69 to improve to four under.

Morikawa leads as Rahm makes case for defence

Morikawa, 25, has already won the US PGA Championship and The Open so would complete the third leg of a career grand slam with the US Open title.

After two bogeys on Thursday he had just one on Friday, and staying patient is his clear gameplan for the weekend as he goes in search of a third major.

“I had one bogey which was a mental error, getting too greedy, so the aim is just to stay patient and not try to force anything out here,” Morikawa said.

Rahm is making a strong defence of his title as he looks to emulate Brooks Koepka in winning back-to-back US Opens, with a 67 putting him on four under alongside McIlroy, Hayden Buckley and Aaron Wise.

The highlight was an eagle on the par-five 14th hole after two typically lusty blows from the 27-year-old Spaniard left him with a 12-foot putt, which he rolled in.

Chip-in sparks Scheffler into life

In the early wave, Scheffler recovered from a duffed a chip from the fairway on the fifth hole, which ended up rolling back down the hill and further away than his initial shot and leading to the first of consecutive bogeys.

But he followed that with three birdies and a 55-yard chip-in eagle on the 14th in a three-under 67 to move to three under.

The 25-year-old is in a great position as he looks to continue an incredible season that has already seen him win five times including his first major at Augusta National.

England’s Fitzpatrick had to grind out a level-par round of 70, but is only three back at two under alongside Sam Burns (67) and overnight leader Adam Hadwin (72).

Fitzpatrick, who won the US Amateur title at this course in 2013, had to battle hard to stay in contention after making three bogeys in a row on his back nine, but the Yorkshireman’s perseverance paid off with birdies on his 14th and 17th holes.

Koepka challenging as Mickelson goes home

Two-time US Open champion Koepka made an eagle on the same hole as playing partner Scheffler, but in a different fashion as he tamed the 616-yard 14th with two muscular blows.

After a booming drive and a crunching iron shot from 271 yards, Koepka rolled in a 14-foot putt to perfectly illustrate the combination of sheer brute force and pinpoint accuracy needed to succeed at the US Open.

A back-to-back champion in 2017 and 2018, Koepka has a stunning record in this event, but he followed that eagle with a bogey to reach halfway at level par.

One man who will not be competing this weekend is six-time major winner Phil Mickelson, who added a slightly improved 73 to his nightmare 78 on Thursday to finish on 11 over.

Recent LIV Golf signing Mickelson has finished runner-up a record six times and the US Open may remain the one major to evade his grasp given the future difficulties he could face getting into the event.

The USGA, which runs the US Open, allowed LIV Golf players to compete this week but has suggested it may make it harder for them to do so.

Fellow LIV Golf competitor Dustin Johnson shot a three-over 73 to sit on one over alongside fellow former US Open champion Justin Rose, who also carded a 73, and US PGA Championship winner Justin Thomas, who signed for a 72.

Belgium’s Thomas Pieters produced a remarkable finish as he birdied four of his final six holes to jump up to level par.