Maryland - Tiger Woods wanted his PGA event to play like a tough US Open-style test and the world number one got his wish in Thursday's opening round of the National at Congressional Country Club.
Thick rough and narrow fairways on the 7,569-yard layout where Rory McIlroy won the 2011 US Open kept players scrambling, although American Roberto Castro solved it for a five-under par 66 to seize a two-stroke lead after 18 holes.
"The golf course is all you can handle," Castro said. "It's long. The rough is brutal. There's not a lot of birdies out there. You're just plodding along. The golf course hasn't changed much in two years."
Woods, absent while recovering from a left elbow sprain, serves as host for the $6.5 million event, which is run by his charity foundation. He used the US Open as a course setup guide, easing up only on green speed and hole locations.
"I would like it to be one of the more difficult PGA Tour events, there's no doubt," Woods said. "It's green. It's lush. It's thick. Temperature's up. It's going to present a hell of a test for the guys."
Canada's Graham DeLaet and Americans Billy Horschel and Bud Cauley shared second on 68, one stroke ahead of a pack of eight on 69 that included Belgium's Nicolas Colsaerts, who shared 10th at the US Open two weeks ago at Merion.
"It's almost like a US Open," Colsaerts said. "It's pretty much the same. The rough is pretty brutal. The greens are probably a lot more receptive than they were at the US Open. That's probably the only thing in our favor."
Castro, who turned 28 on Sunday, began on the back nine and took his lone bogey at the 11th, then answered with birdies at the par-4 12th and par-3 13th, another at the par-4 first and then a sizzling run of three birdies in a row capped by a 15-foot chip-in at the par-3 seventh.
"Made a couple good par saves, made a couple good shots out of the rough which is what you are going to have to do out here," said Castro, whose best PGA finish was a share of seventh at last year's Greenbrier Classic.
Horschel won his first PGA title two months ago at New Orleans and produced his best finish at a major with a share of fourth at Merion.
"It's like another US Open," Horschel said. "It's not easy. Off the fairways the rough is thick. Got to drive the ball really well here to give yourself opportunities.
"I've always felt like the tougher the golf course, the better I play."
Missing the chance to challenge Woods at his own event was no big deal for Horschel, who said, "Tiger is Tiger. He's just another guy. He's just another player out here."
Australian Jason Day, a runner-up at Merion who was second to McIlroy in the 2011 US Open at Congressional, took a bogey at 18 to finish on 70.
"It was a tough old day," Day said. "It was playing just as long as a US Open course. I've had good success around this course. I played pretty good out there."
Aussie Adam Scott, the reigning Masters champion who was third in this event the past two years, opened on 73.
South African Rory Sabbatini was 8-over par after 12 holes and withdrew with a back injury while Davis Love pulled out with a hip injury after an 83, his highest score since the first round of the 2010 Houston Open.
Leading scores on Thursday after the first round of the $6.5 million US PGA National at par-71 Congressional Country Club (USA unless noted):
66 - Roberto Castro
68 - Billy Horschel, Bud Cauley, Graham DeLaet (CAN)
69 - Ben Kohles, Jim Furyk, Nicolas Colsaerts (BEL), Fabian Gomez (ARG), Russell Henley, Brandt Snedeker, Jordan Spieth, James Driscoll
70 - Andres Romero (ARG), Vijay Singh (FIJ), Bill Haas, Angel Cabrera (ARG), Nick Watney, Chris Stroud, Shawn Stefani, Brian Davis (ENG), Kevin Chappell, Gary Woodland, Stewart Cink, Jason Day (AUS), K.J. Choi (KOR), Freddie Jacobson (SWE), Tom Gillis