Woods, who is seeking a 15th major title and a first since 2008, was among the early starters hoping to make a flying start in baking temperatures in St Louis, only to drop three shots in his first two holes.
But after changing his shirt in a players’ bathroom between the 11th green and 12th tee, Woods fought back to card a level-par 70 and lie five shots off the clubhouse lead held by fellow American Rickie Fowler.
Fowler carded six birdies and a solitary bogey in a 65 which gave him a two-shot lead over playing partner Ian Poulter, former world No 1 Jason Day, Austin Cook and Pat Perez.
Defending champion Justin Thomas had been three under after six holes before two bogeys on the inward nine meant he had to settle for a 69, while Rory McIlroy parred his last nine holes in succession in his 70.
Starting on the back nine alongside Thomas and McIlroy, Woods missed the fairway with his drive on the tenth, a par four of more than 500 yards which plays as a par five for the members.
From a bad lie in the rough Woods opted to simply pitch out on to the fairway and, after a poor approach and weak first putt, did well to hole from six feet for a bogey.
Woods also missed the fairway on the 11th and his approach found the water in front of the green, but after a mediocre pitch from the drop zone led to a double bogey, a superb approach to the next set up a tap-in birdie.
The 42-year-old did well to save par on the 15th after pulling both his tee shot and attempted recovery into the crowd, but was unable to repeat the feat on the par-three 16th after another wayward approach.
However, Woods did hole from three feet for birdie on the 18th and ten feet on the first and another birdie on the par-five eighth completed a superb comeback.
Woods was delighted to have turned his day around and remain in contention for a first victory since 2013.
“It kept me in the golf tournament,” Woods said. “It could easily have gone the other way but I hung in there and turned it around. I’m just happy to be within five [of the lead] right now.
“I just had to grind my way around this place. I tried to stay as patient as possible after I got off to a terrible start and tried to eat away at it. These are four long days; it’s a marathon.”
Asked about his change of shirt, Woods added: “I was going to change before the start but there wasn’t a place to change on the tenth tee so I waited until there was a toilet.
“I sweat a lot in the summer and lose a bunch of weight; I’ve tried everything and just sweat a lot.”
Meanwhile, McIlroy is braced for a “crazy” second round after experiencing Tiger-mania in St Louis.
The marquee group of McIlroy, Woods and Justin Thomas drew massive galleries for an 0823 tee time yesterday morning, and the crowd is likely to be even bigger when the star trio begin their second rounds shortly before 2pm today.
“It was pretty cool to be out there 8:30 in the morning and have an atmosphere like that,” McIlroy said. “JT and I were saying it’s going to get a little crazy tomorrow afternoon. So we’re looking forward to that.
“Harry [Diamond] caddied for me in the 2005 Irish Open when I was 16 and then we’re walking the fairways in a group like this today, 13 years later. So it’s pretty cool.”
McIlroy wore an anti-inflammatory patch on his right arm as he compiled an opening 70 which featured two birdies and two bogeys on the outward half and nine pars in a row to finish.
“I started feeling it the weekend of Firestone,” the 29-year-old said. “It hurts the most with chipping because I sort of hold the angle a little bit. The whole forearm has been tight.
“I hit a lot of balls last week at Firestone working on a few things and it’s just a little inflamed and a little tight, but it’s fine.”