Bethesda - Tiger Woods struggled to a three-over par 74 on Thursday in his PGA return after a three-month injury layoff, but was optimistic after birdies on three of his last six holes at the National.
The 14-time major champion failed to consistently summon the skill that drew worldwide audiences in his first comeback round, but he improved at the finish in his first warmup for next month's British Open.
"The more I played, the more I felt comfortable about shot selections, my sight lines, all different things," Woods said. "I played a lot better than the score indicated, which is good."
Woods, who shares 83rd place, figures to be battling just to make Friday's cut to the low 60 and ties at the $6.5 million event, standing eight strokes behind first-round leader Greg Chalmers of Australia.
On a Congressional Country Club layout where Woods won in 2009 and 2012, he struggled early after not playing competitively for 109 days due to back surgery to relieve a pinched nerve.
But Woods said his back was in "great" shape, and did not bother him at any point in the round.
Starting off the 10th tee, Woods opened and closed the back nine with back-to-back bogeys, then made bogeys at the second and third to fall 10 strokes off the pace.
"I made so many little mistakes," Woods said.
He responded with a birdie at the fourth hole and consecutive birdies at the seventh and eighth.
"The hard part was just getting into the rhythm of playing competitively," Woods said. "Adrenaline is rushing and I hit the ball further out here than I do at home."
Woods, chasing Jack Nicklaus's all-time record of 18 major titles, hopes to play his way into shape this week ahead of the British Open at Royal Liverpool, where he won the Claret Jug in 2006.
"It's a little different starting out and he finally found his rhythm," said Woods playing partner Jordan Spieth. "So look for a pretty solid round tomorrow out of him. Wouldn't be surprised if he shoots a few under."
Woods, who has not won a major title since the 2008 US Open and not broken 70 on the weekend at a major since the 2011 Masters, had not played in any event since March 9 at Doral, where he fired a 78, the worst final-round score of his pro career.
His 79 career titles are three shy of matching Sam Snead's PGA record, and he has not won since last August's World Golf Championships event in Akron, Ohio.
The 38-year-old American, nagged by leg and knee injuries in recent years, spent months recuperating and slowly progressing to the point where he could swing a driver at full strength and he continues to take physiotherapy exercises.
"It really is (a relief). It's nice to get back out here playing again," Woods said. "I've been held back where I just haven't been able to let it go. Now I'm able to start doing that. That has always been the challenge."
Overtaken last month by Aussie Adam Scott for the world number one spot, Woods has fallen to fifth in the rankings while idled.
He began his comeback at the par-3 10th by sending his tee shot over the green and into a bunker, blasting out to 17 feet and missing a par putt.
At 11, Woods left his approach short of the green and missed from 18 feet for par.
Woods dropped a 174-yard approach nine feet from the pin at 14 and made the birdie putt, but pulled his next tee shot left into the rough and made bogey at 15.
Woods missed a six-foot birdie putt at the par-5 16th, took two bogeys to make the turn and two more on the second and third.
But he bounced back with four-foot birdie putts at the fourth and par-3 seventh and dropped his approach at the eighth three feet from the cup to set up yet another birdie and provide hope for reaching the weekend.
"I drove it great. I felt comfortable," Woods said.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 - Greg Chalmers (AUS)
67 - Ricky Barnes, Freddie Jacobson (SWE)
68 - Patrick Reed, Erik Compton, Bill Haas, Tyrone van Aswegan (RSA)
69 - Hudson Swafford, Nick Watney, George McNeill, Billy Hurley, Spencer Levin, Retief Goosen (RSA), KJ Choi (KOR), Michael Putnam
70 - Daniel Summerhays, Cameron Tringale, Tim Wilkinson (NZL), Stuart Appleby (AUS), Brandt Snedeker, Andres Romero (ARG), Morgan Hoffmann, Geoff Ogilvy (AUS), Billy Horschel, Marc Leishman (AUS), Oliver Gross (AUS)