OAKMONT - Shane Lowry kept his calm when he had a careless penalty stroke and walked off Oakmont after a long day with a two-shot lead in the U.S. Open.

Stalled by rain in the first round, the U.S. Open is nearly back on schedule and poised for a big finish.

Lowry, looking to give Irish golf a 10th major in the last 10 years, was at 5-under par with four holes to play in the third round when it was too dark to continue.

Andrew Landry, the 28-year-old qualifier in his first U.S. Open, was two shots behind.

Dustin Johnson had the 36-hole lead and opened with a birdie to start the third round. He began dropping shots and was three behind, along with Lee Westwood and Sergio Garcia.

And still very much - and very suddenly - in the mix was Jason Day, who shot 69-66 on Saturday and was at 1-over 211.