OAKMONT - Dustin Johnson saw his US Open lead come under threat from several players on Saturday, but when the delayed second round finally ended he was still ahead with the third round set to follow.

Absent from that will be Rory McIlroy, Phil Mickelson, Justin Rose and Rickie Fowler, who all failed to survive the cut. Johnson, the big-hitting American who still awaits his first major title despite several close calls, set the pace at four-under late Friday with a 69 that he squeezed in minutes before darkness set in over Oakmont near Pittsburgh.

He was then able to put his feet up and watch if anyone from the rest of the field could match or better him early Saturday and, as it turned out, no one could. Veteran Englishman Lee Westwood briefly got to five under, but promptly fell away. Then lowly-ranked Frenchman Gregory Bourdy nudged into the lead only to come undone with a double-bogey six at the last.

Finally, it was surprise first round leader Andrew Landry who ended up closest, birdies at 17 and 18 hauling him up to three-under after he had shed four strokes in three holes from the sixth. The Texan, ranked 624th in the world, settled for a 71 to go with his fine opening 66 and he was one shot adrift of Johnson for the lead at the halfway stage.

"Obviously, birdie, birdie to end my second round is a way to get my momentum going in the third round. I'm looking forward to it," he said. Bourdy, who had a 67, finished in a four-way tie for third place along with American Scott Piercy and Spain's Sergio Garcia, who both had 70s late Friday, and Ireland's Shane Lowry.

"It was a beautiful golf and I knew at the beginning of this week, I could do something well. I feel very good in my game the last few weeks, and I really love the difficulty of this course," the 126th-ranked Bourdy said. "I can play some great tee shots, good irons. And today, I holed some putts as well, so A-plus. At the end it was a very good day on a very difficult course like this," he said.

On one-under were Americans Daniel Summerhays and Jim Furyk alongside England's Andy Sullivan and Westwood who bounced back with two birdies in the last three holes. "I didn't panic out there. Just kept trying to grind it out. Missed it in the right spots if I did miss it. Just picked up the odd shot if I could. That's about all you can really say about that round," Westwood said.

Those 10 players were the only ones to be under par at the halfway stage on a course rated one of the toughest in the world. The cut came at six-under leaving 67 golfers to go forward to play in the third round later Saturday, the plan being to complete that and get back on schedule by the end of the day.

MCILROY DOOMED:

Among those missing out were four-time major winner McIlroy. The Northern Irishman opened in style with four birdies in seven holes, but he then four-putted the third -- his 12th of the day -- and a double-bogey at the last doomed him.

McIlroy shot 31 for his first nine and 40 coming back for a 71 and an eight-over total. It was the first time he had missed a cut in a major since the 203 British Open at Muirfield.

Six-time runner-up Mickelson saw his dream of completing a career Grand Slam once again shattered and also packing their bags were 2013 winner Rose and a totally out-of-form Fowler who was 11-over.

Defending champion Jordan Spieth failed to find any consistency, five bogeys more than off-setting three birdies for a 72 that left him at four-over. Earlier in the day, world number one Jason Day completed a 69 to ensure he would make the cut. But at five-over he had a lot to do if he is to add the US Open crown to the PGA Championship he won last year.

"I'm trying to claw my way back to even par," The Australian said of his strategy for the third round. "I think, if I can get back to even par, that I may have a good chance at giving myself a shot at winning.