Phil Mickelson, who has suffered more US Open heartache than any other player, thrilled his fans as he moved into contention for the only major title which has eluded him.

The American left-hander, who has been a runner-up in his national championship a record six times, ground out an even-par 70 in the opening round at Pinehurst Resort to finish two strokes off the early pace.

"I drove it great," admitted the five-times major winner, whose most recent runner-up finish at the US Open came last year at Merion.

"Every time I hit the driver, I hit the fairway. I putted OK but didn't make the ones you need to make to have a good round."

American Kevin Na opened with a 68 on Pinehurst's fabled No.2 Course where danger lurked on virtually every hole because of the unique turtle-back greens.

"I got off to a great start," Na said after mixing an eagle at the par-five fifth with three birdies and three bogeys on an increasingly firm and fast-running layout. "I had an early tee time and I was able to capitalise on that. A long way to go and I'm obviously at two-under par right now but, at the end of the tournament, I think even par is going to win this championship."

Brent Snedeker carded a 69. "I don't know how I made six birdies today, you're not going to have that very often," he said. "I got off to a great start."