World number one Woods, who has struggled through the longest win drought of any year in his career, fired seven birdies against a single bogey at Ridgewood Country Club to seize the clubhouse lead with most of the field still playing.
In the first US PGA playoff event, defending champion Woods needs to finish at least 57th to ensure he continues to advance to next week's event at Boston.
Woods, whose split from Elin Nordegren after a humiliating sex scandal was made official on Monday, served notice to rivals that he can still perform at a top level after months of misery, most of which he kept to himself."It was a lot more difficult than I was letting on," Woods said Wednesday of his divorce. "Most of the summer was like that. You try to block it out, but yes, at times it was (very painful)."
Woods has not won in nine events this year, the worst stretch of his fabled career. The 34-year-old American has gone 10 majors without a title, matching his longest drought.
Just 18 days earlier, Woods finished off the worst 72-hole score of his pro career, an 18-over par 298 at the World Golf Championships Bridgestone Invitational, on a course where he had won seven prior titles.
Not since 2003 had Woods fired over par in every round of an event.
But after he sizzled to the top of the leaderboard on Thursday, Woods appears to be back in the prime form that has seen him win 14 major titles, four shy of the all-time record set by Jack Nicklaus.
It should all-but seal his selection for the US Ryder Cup team that will defend the trophy against Europe in October in Wales.
Woods opened Thursday with a birdie and made birdies on every other hole through the seventh, missing a 15-foot eagle putt at the par-4 fifth.
After taking his only bogey of the round at the par-4 12th, Woods answered with back-to-back birdies on the next two holes and closed with a birdie at the par-4 18th to seize the lead.
He holed birdie putts from 14 and 18 feet and showed the consistency he has sought all season. His best showings have been shares of fourth at the US Open and Masters.
"I came back. This is part of my job. It's what I do," Woods said. "Me coming back and playing golf had nothing to do with our decision to move our separate ways."
Woods has been working with swing coach Sean Foley the past few weeks and had some sessions last week at home in Orlando preparing for The Barclays.
"Obviously I will get my game in order, work on some things with Sean and hopefully play well the rest of the year. I have to play well to get to next week," Woods said.
"Winning takes care of everything."
Dealing with the wreck he had made of his personal life has proved difficult for Woods as he struggled to find the precision putting and accurate shotmaking that has made him the greatest player in golf for decades.
"That was always difficult, especially when I'm trying to find a few golf shots to work my way around the golf course," Woods said.
Asked if this was a lost year given his personal turmoil and inability to win a title, Woods noted that while there were a lot of bad things and he had brought much of it upon himself, there was light at the end of the tunnel.
"I learned a lot about myself and how to be a better person," he said. "There are a lot of positives."
