Collin Morikawa held a share of the US Open lead after a riveting second round on Friday while defending champion Jon Rahm and tournament favourite Rory McIlroy sat one shot back on a star-laden leaderboard.

Twice major champion Morikawa fired a four-under-par 66 that was the day’s low round and left him at five under on the week at The Country Club outside Boston and level with little-known qualifier Joel Dahmen (68).

“No one has taken it deep so far and kind of run away, but you know what, right now my game feels really good,” said Morikawa, who is the only player currently in the top 10 of the world rankings without a PGA Tour win this season.

“The last few days is a huge confidence booster for me heading into this weekend, and hopefully we can kind of make some separation somehow.”

Dahmen, who considered skipping a recent US Open qualifier so he could concentrate on upcoming PGA Tour events where he figured he would fare better, missed a 10-foot birdie putt at the last that would have given him the solo lead.

World No. 2 Rahm (67) enjoyed another solid day on the greens to move up the leaderboard, while No. 3 McIlroy (69) overcame a shaky start to share third place along with Hayden Buckley (68), Aaron Wise (68) and Beau Hossler (67).

Lurking a further shot off the pace were a pack of five golfers that featured reigning Masters champion and world number one Scottie Scheffler (67), setting the stage for what could be a wild weekend at Brookline.

While a leaderboard with the top three players in the world rankings within two strokes of the lead is a fan’s dream going into a major weekend, even Rahm is excited about the chance to go toe-to-toe with his peers on one of golf’s biggest stages.

“It’s fun for all of us because we all want to compete against the best and beat the best, and it’s obviously a lot more fun for watching,” said Rahm.

Morikawa began on the back nine and had a glorious chance to build a two-shot lead when his approach at the par-five eighth settled four feet from the cup, but he sent his eagle attempt right past the cup and settled for birdie.

Dahmen, who considered skipping a recent US Open qualifier so he could concentrate on upcoming PGA Tour events at which he figured he would fare better, missed a 10-foot birdie putt at the last that would have given him the solo lead.

“It’s kind of been a whirlwind really,” said Dahmen.