Updated

By Julian Linden

KOHLER, Wisconsin (Reuters) - American Matt Kuchar made the most of a timely break in the inclement weather to grab the clubhouse lead in the second round of the U.S. PGA Championship on Friday.

Kuchar added a 69 to his opening round of 67 to reach the halfway stage at eight under par and leading by one shot from his countryman Nick Watney, who carded a 68, with a group of seven players, including Britain's Rory McIlroy and South Korean teenager Noh Seung-yul, two shots further back at five-under.

Exactly half of the 156-player field, including world number one Tiger Woods, failed to finish their second rounds after spending most of the day cooling their heels following another delayed start at the Whistling Straits course that hugs the coastline of Lake Michigan.

Almost six hours were lost on the first two days because of the thick blanket of fog each morning, leaving organizers scrambling to get the last major of the year back on schedule.

Kuchar was among the 78 players who had to complete their opening rounds early on Friday morning but then got the benefit of going straight back out to play their second rounds before the wind picked up late in the afternoon.

"This is certainly a great place to be," said Kuchar, whose best finish at a major was tied for sixth at this year's U.S. Open. "I'm looking forward to the opportunity to really do something great this weekend."

Britain's Simon Khan briefly joined Kuchar at eight under but bogeyed the last three holes to slip back to a tie for third and leave Watney as Kuchar's closest challenger.

"The course really showed teeth today," Khan said.

South Africa's Ernie Els also had trouble at the end of his round, finishing with a double bogey to end on two under.

"It's not how you want to finish. It was a difficult day," said Els. "I scrambled quite well here and there but just let it go at the end there."

U.S. Masters champion Phil Mickelson had an up and down day, struggling to find the fairway, but holed some long putts for a 69 to join Els at two under.

"I just want to be in a position where if I play like I know I can, I can make up some ground," he said. "And I feel like I'm within striking distance."

TOUGH CONDITIONS

Woods, who shot 71 on the opening day, made a solid start to his second round, scrambling to par his first six holes to remain at one under when play was suspended because of fading light.

"It was tough out there, blowing pretty good, had to be very patient," Woods said.

"I had to hang in there and did a good job with that. Unfortunately I missed a short one (putt) there at the last one I played but other than that, it was all right."

American Jason Dufner shot a superb 66, the lowest completed round of the championship, to join Bryce Molder (67), Dustin Johnson (68), Zach Johnson (70), McIlroy, Khan and Noh at five-under.

"I feel as if I'm in a really good position going into the weekend and I like the position I'm in," the Northern Irishman said.

"Only three behind at the minute. We'll see how the guys in the afternoon make out, but I feel as if I'm in a strong position and a position where I can make a charge for the weekend."

McIlroy was joined by Noh, who birdied three of his five remaining holes for a first round 68 then added 71 in the afternoon.

South Africa's British Open champion Louis Oosthuizen carded a 75 to finish at two over, one better than Britain's U.S. Open winner Graeme McDowell, who rebounded from his first round 76 with a 71, but both were in danger of missing the cut.

(Editing by Greg Stutchbury; To query or comment on this story email sportsfeedback@thomsonreuters.com)

(julian.linden@thomsonreuters.com; +1 646-552-9780. Reuters Messaging: julian.linden.thomsonreuters.com@reuters.net; For the sports blog Left Field go to: blogs.reuters.com/sport/))

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