Australia's top-ranked golfer followed up his opening round 78 with a 77 on Friday (Saturday AEST) to plummet to 11 over par for the championship.
The 27-year-old had entered the season's first major brimming with confidence following a succession of top-10 showings at the PGA Tour's Signature events in 2026.
But he confessed to completely flopping on golf's grandest stage.
"Making two birdies out here in 36 holes is not going to cut it. Didn't have my best at all," Lee sighed.
"I don't know. I mean, the preparation was unbelievable. You would think I would be winning the tournament the way I was playing leading up to the event.
"But it's not like I was nervous or anything. I just kept hitting the same shot, which was weird.
"Yeah, I had a lot of support and had a lot of people supporting me to play well so a little bummed that I couldn't get anything going."
The world No.25 candidly conceded he needs to be better on his next trip to Georgia.
"It's pretty straightforward: just got to hit it straight and hit the greens," he said.
"Don't think I hit many greens.I felt like I had five birdie chances throughout 36 holes, which is not that good.
"Didn't drive it good and you needed to do that around here. Just give yourself chances and, when I did have an iron in my hand, it would not be the shot that I wanted.
"It's one of those courses. You've got to be accurate - I think that's the biggest takeaway.
"You hit it in the wrong spot and it just costs you so much. You don't need to attack the course too much. Just plot along and give yourself chances."
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