By Mark Lamport-Stokes
OAKMONT, Pennsylvania (Reuters) - Dustin Johnson's overnight lead held up after a see-saw second round at the weather-disrupted U.S. Open was finally completed in dazzling afternoon sunshine at Oakmont Country Club on Saturday.
England's former world number one Lee Westwood and Frenchman Gregory Bourdy had turns at the top as they moved one stroke clear but they both fell back as the treacherous Oakmont layout became faster and firmer.
The long-hitting Johnson, who missed a three-foot putt at the final hole to hand last year's U.S. Open to Jordan Spieth, had produced superb form from tee to green to card a one-under-par 69 before play was suspended in fading light on Friday.
That left him at four-under 136 and by the time the marathon second round concluded at Oakmont, he was one shot in front of PGA Tour rookie Andrew Landry, the surprise first-round leader.
"I hit some really good shots there coming in," said Landry, who birdied three of his last six holes. "The green speeds have really cranked up a little bit. Balls are starting to release a little bit."
Landry, the world number 624 who is competing in his first U.S. Open, recovered from a poor start to card a 71, finishing a stroke ahead of fellow American Scott Piercy (70), Spaniard Sergio Garcia (70), Ireland's Shane Lowry (70) and Bourdy (67).
Bourdy had briefly surged one ahead of the field with back-to-back birdies at 13 and 14 following a stunning eagle two at the 11th, where he holed out from 137 yards, but he tumbled backwards with a bogey at the 16th and a double at the last.
"I really love the difficulty of this course," said Bourdy. "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."
Westwood also got to five-under with birdies at the first and fourth before he faded with a run of five bogeys in six holes round the turn on the way to a 72 and a one-under total.
"The mistakes I made weren't killers, weren't disastrous," said Westwood, still seeking his first major title after 18 top-10s in grand slam events.
"They were only bogeys, and then I finished strongly with two birdies on the last three holes."
Defending champion Spieth ground out another 72 to finish at four-over but several big names missed the cut, which was set at six-over 146. Also advancing were Australian world number one Jason Day (69/145) and Masters champion Danny Willett (70/145).
Among those failing to join the 67 players who qualified for the third round, were 2011 champion Rory McIlroy (71/148), fifth-ranked Rickie Fowler (75/151) and five-times major winner Phil Mickelson (73/147).
Swede Henrik Stenson, who had opened with a 69 but struggled in the second round, did not return to the course on Saturday and withdrew from the tournament, citing minor neck and knee issues.
Players turned right around as third-round play began at 3 pm ET . Organizers hope to get the third round finished on Sunday morning, before completing the regulation 72 holes by the end of the day.
(Editing by Larry Fine)