Sublime Swede Ludvig Aberg claimed a one-stroke halfway lead in a dream U.S. Open debut on Friday but said his biggest "pinch-me moment" at Pinehurst might be playing alongside the stars he has long admired.

The tricky North Carolina course humbled some of the biggest names in the sport this week but could not slow down the 24-year-old Aberg, who had three birdies and two bogeys for a 1-under-par 69 to reach 5-under on the week.

"Sometimes I have to stop for a little bit and think about how fortunate I am to be able to do this at this level," said Aberg.