Former world No.1 Adam Scott and major championship rookie Cameron Smith have put together solid starts to the US Open at Chambers Bay.

Scott spent some time early in his round tied for the lead but is now even par through 10 holes to be tied ninth, four shots behind American Patrick Reed who is four under through nine.

Smith, just 21 years old and in his maiden major, is also even par through 15 holes, an impressive effort considering he carded an early double bogey.

Phil Mickelson, searching for the last leg of a career grand slam, is three under through 12 holes to hold second place where he is joined by fellow American Dustin Johnson (10 holes).

Starting on the 10th, Scott opened his tilt with a three-foot birdie and was two under with another birdie on the 12th to hold a share of the lead.

But a couple of missed birdie chances on 13 and 14 were compounded by a bogey on the 15th and a pulled birdie putt from 10 feet on the 18th was rued when he made bogey on the first.

Smith, also starting on the back nine, opened with three pars, one of which included a clutch 30-foot putt.

But a wayward drive on the 13th hole, his fourth, followed by an approach that finished in the sand, left him with a double-bogey six.

The rookie bounced back with back-to-back birdies and was under the card when he birdied the 18th but a bogey on the second hole dropped him back even.

Marcus Fraser is one over through 15, John Senden two over through 13 and Kurt Barnes is three over through 14 holes.

World No.1 Rory McIlroy is even par through eight holes. Geoff Ogilvy, Marc Leishman and Jason Day are due out in the afternoon wave.