Tiger Woods says he is relieved to be in contention at the PGA Championship after recovering from a disastrous start to his opening round at Bellerive Country Club.
The four-time winner, who featured in a marquee grouping alongside defending champion Justin Thomas and Rory McIlroy, bounced back from an unpromising bogey, double-bogey start to record a level-par 70 amid humid conditions St Louis.
Woods, playing in the event for the first time since 2015, admits he needed all of his battling qualities to remain in the frame for a first major victory since the 2008 US Open.
"It kept me in the golf tournament," said Woods, who admitted he changed shirts following his double-bogey at the 11th - a move which paid off immediately as he knocked a superb seven-iron to two feet for a bounce-back birdie at the next.
"I could have easily gone the other way, being three over through two. A lot of things could happen. Not a lot of them were positive, but I hung in there and turned it around."
Asked about his change of shirt, he added: "As you know, I sweat a lot, and I lose a bunch of weight. I have the hardest time during summer maintaining weight. No matter what I eat, no matter what I drink, I just can't maintain weight. So this heat is one of the issues that I have.
"Normally I change before the round, but there wasn't a place to change on the 10th tee. So I waited until we had a little port-a-John there."
Woods, who has spoken of his determination to seal an automatic spot in the USA team for the Ryder Cup, said his birdie at the 18th - the final hole of his front nine - was crucial in providing some momentum.
"As I said, if I could just give myself a few putts at it, I could turn this thing around. I made a couple of good putts, but the shot at 18 was just a little 7 iron," Woods added.
"It was nice to kind of turn the tide going into the back nine with that birdie."
The 42-year-old held the lead during the final round of The Open at Carnoustie last month and Woods says he feels sharp for another tilt at a major triumph, having minimised his preparation.
"The main thing about major championships is to make sure you have enough energy. This is a long run," he said.
"These are marathons. These are four long days. They're slow rounds. They're not quick. Certainly not under these conditions. And with the setup, the rounds are going to be slow."