Tiger Woods staged a superb recovery from a torrid start to give himself a "fighting chance" of contending for a sixth victory at The Memorial.
Woods struggled with a tight back early in his first round and slumped to four over par after seven holes before hitting back with five birdies to salvage a level-par 72 which left him seven shots behind the early clubhouse leaders at Muirfield Village.
The 42-year-old started with a cast-iron par at the 10th, but he was soon in trouble on the par-five 11th when, after pitching back out to the fairway following a wayward drive, his ambitious third failed to clear the water hazard protecting the front of the green.
The mistake led to a bogey-six, and worse was to follow at the 15th when he carved his drive out of bounds and ran up a seven, after which he bunkered his tee shot to the short 16th and could not get up and down.
But he began to repair the damage on the next green when he converted a solid approach to 11 feet, and he clawed another shot back at the short second only to three putt from 20 feet two holes later.
Woods, making his first appearance in the event since 2015, then dug deep to reel off three consecutive birdies, and he scrambled a good par at his final hole with a confident six-foot putt.
"I wasn't rotating very well today, back was tight, and just it is what it is some days," he said afterwards. "I made a few tweaks in my swing, my setup, and lo and behold I was able to make some good swings on my back nine, and turned the whole thing around so at least I've now got a fighting chance.
"It is what it is. I've just got to make the adjustments and I'm able to make them now. At the beginning of the year, I wasn't able to make them, because I didn't really know what to do yet. But now you see me making these adjustments on the fly.
"I have days like that. My back is fused and I'm going to have days where it's just tight. Unfortunately today was one of those days and that's all right. I don't have any pain, thank God. It's just tight, so no big deal."