Having taken the first set against Tsvetana Pironkova, the British No. 1 appeared to be struggling in the conditions at Flushing Meadows and was red in the face, with temperatures also reaching 31 degrees Celsius on Wednesday.
She began to hyperventilate while serving to force a tiebreaker in the second set on Court 13 and then fell to her knees on the baseline.
Konta gasped for breath as she sat down on a towel with bags of ice under her arms before the trainer arrived. She then lay on her back as the trainer and doctor took her blood pressure before helping her back to her chair, where she had her legs rubbed with ace.
"I was feeling a little bit the conditions, and my own energy levels," she told a press conference. "My heart rate spiked and I couldn't really control my breathing. I started hyperventilating. I started shaking. That's why I went down on the ground, because I was quite violently shaking.
"We are very fortunate with the medical staff that we have here. Once they came out I did panic a little bit. They kind of calmed me down. They did all the necessary checks to see how I was doing immediately then. Since then I've done all the necessary checks, as well. So, yeah, all should be good."
Play eventually resumed after several more minutes, and Pironkova quickly wrapped up the second set, with Konta then leaving the court for her second toilet break of the match.
Still red in the face, the Briton returned and immediately broke Pironkova in the deciding set before closing out a 6-2, 5-7, 6-2 win. Konta then stayed in her seat for several minutes, turning down an on-court interview request from a television broadcaster before leaving.
"I did not think of whether I was pulling out, whether I was continuing to play," she added. "I was taking it basically each second, each minute as it came. I think I just did good management in the third set. I was definitely just playing with what I had energy level-wise, feeling-wise, everything-wise.
"I was just focusing on my breathing, making sure I was keeping my breathing as level as possible."
Pironkova admitted she was thrown off her game by the lengthy delays.
"We lost some time there with the medical timeout and the treatment," the Bulgarian told reporters. "What was frustrating for me was what happened after that, the toilet break, because I think the match was stopped for just too long.
"It was an unfortunate time for me, I had my momentum going, was getting back in the match. Probably that break somehow maybe stopped that momentum, but then again I don't want to make excuses for myself.
"To be able to go and change your clothes after every set, it didn't work out good for me today, but these are the rules. I wish I could say all the players use them [toilet breaks] accordingly to go to the toilet but obviously some use them to refocus. I don't think they should be used that way. If I don't need to go to the toilet, I don't do that."
Konta said she felt "embarrassed" by the incident but defended her decision to depart the court at one-set all.
"The way it worked out with the medical timeout, it was right at the end of that second set," she said. "I needed to get changed out of my clothes. I was soaked through.
"I'm not a fan of drama. I did the best that I could with the cards that I had. My opponent, she was gracious, and she was also very, I felt, understanding of the situation that was going on.?
"It's not a situation that I'd want to be in. It's not a situation I'd want anyone to be in. I'm out there to play my sport, to showcase my sport. I'm not an actress. I'm not a drama queen.
"To be in a situation where it's quite a vulnerable situation, yeah, it's not a humbling experience, but it does kind of take you back a bit. It's a bit of a shock to the system. That's all."