Leader Madelene Sagstrom certainly didn’t experience the 41C/105.8F afternoon heat index in her home country of Sweden, but she did attend Louisiana State University, now lives in Orlando, Florida, and has played in even worse furnace-like conditions in Thailand and Singapore.

That said …

“I'm not going to lie, it's very hot,” Sagstrom said after shooting five-under-par 66 to take a one-stroke lead over World No. 1 Nelly Korda of the USA and Aditi Ashok of India. “But it's manageable. I know I mean most of us have been in Asia, played a lot of golf over here so we know kind of what to do, you drink a lot of water you have cooling towels, umbrellas, kind of just maintaining the energy and not go crazy. I think at this point it's harder for the caddies than it is for the players, so it's more about making sure they're staying upright.”

Which, in fact, has been a problem.

Hannah Green sought protection from the heat via a bucket hat on her way to an opening 71, the same score as compatriot and fellow major winner Minjee Lee. PHOTO: Mike Ehrmann/Getty Images.

On Tuesday, U.S. Women’s Open champion Yuka Saso had to replace her caddie due to the heat. And today, American Lexi Thompson lost her regular caddie, Jack Fughum, on the 15th hole and had team manager Donna Wilkins step in to finish the round.

“I was so worried about him and, I mean, it's so hot out there,” Thompson said after a difficult round of 73. “I'm from Florida and I'm still not used to that bad of heat. I just hope that he's okay and he gets the hydration he needs, the nutrients tonight to go into the next few days. If not, I'll figure something else out. I just want him to be healthy.”

Korda is another Floridian who is used to hot playing conditions, but after her round, she admitted to being light-headed a couple of times when teeing up her ball.

“I think the mental aspect of it is probably the hardest just because you have to keep yourself hydrated and you kind of lose it a little out there,” she said. “But I kept myself in it, made sure I drank a lot of electrolytes, too.”

So, Wednesday, in part, became a matter of survival, with Sagstrom coming away as the leader after a clean six-birdie, bogey-free round.

LEADERBOARD

“I would say mostly my short game was kind of my saviour,” she said. “I was striking the ball all right but not great, so having a strong short game and just giving myself the chances, like solid par chances was kind of the key of my round today.”

Sagstrom then echoed a consistent Olympic golf theme by praising the East Course and its condition.

“This course is beautiful,” she said. “The condition of it has been perfect from the start. I like long golf courses in general and it fits my game really well, so very excited with the layout, it suits my eye and the greens are rolling phenomenal which works with my putting too. So, it's phenomenal.”

Korda, meanwhile, after parring the first hole, went bogey-birdie-bogey before birdieing three of the next four holes, then played consistently on the back with two more birdies.

“I'm hoping I'm in total control,” she said. “I kind of sprayed some shots out to the right on my last two holes with my irons, but you're going to have that, you're going to lose a little bit of concentration, but I'm going to go to the range after, after I cool off inside for a bit and then try and work on it.”

After Korda finished, Ashok came in with a chance to finish at five-under by herself but bogeyed the final hole.

“I think I played better than I expected today because I had a lot of hybrids into the greens, so I didn't really expect to be like 5-under through 17,” said Ashok, a returning Olympian who was the youngest golfer five years ago in Rio at age 18. “But, yeah, I kind of holed some putts and holed important par putts as well which kept the momentum. So, yeah, it was a good day.”

Another stroke back at 3-under 68 are Matilda Castren of Finland, Jin Young Ko of Korea and Carlota Ciganda of Spain. They are followed by nine players at 69, including returning gold medallist Inbee Park and teammate Sei Young Kim of Korea.

There’s also Wei-Ling Hsu of Chinese Taipei, who settled at 69 after taking the early lead with birdies on five of the first six holes … perhaps inspired by the outstanding performance of compatriot C.T. Pan on Sunday.

She helped celebrate after Pan recovered from an opening 74, shot a closing 63 to make a seven-way playoff for the bronze, then emerged as the last man standing against the likes of Japan’s national golf hero Hideki Matsuyama, Ireland’s Rory McIlroy and American Collin Morikawa, who was the last to fall.

As the world’s 208th-ranked player at the time, Pan outlasted these three players who have combined for seven major championship titles, including two this year. Once Pan beat Morikawa with a par at the 18th hole, Hsu was among several who rushed the green and doused Pan with water.

“That was amazing, what C.T. did,” Hsu said. “I was practicing here on Thursday and I think he shot like three-over (on Thursday) and he is just amazing. He kept making birdies and in the playoff with seven people, he played another four holes. I was able to be in there to watch him and recognize that someone from Chinese Taipei was able make a bronze medal in front of me. I was able to watch the ceremony and I was tearing in my eyes. I was so touched. It was just incredible. It’s so touching every time someone wins a medal which is an inspiration to me.”

The Australian women didn’t put their name up in lights nor take themselves out of the medal race on day one. Both Hannah Green and Minjee Lee signing for even par rounds of 71.

Lee made a number of birdies offset by bogeys, and echoed the thoughts of the other players about the heat in a very Aussie way.

“Oh, it was bloody hot. Yeah, it was really hot. I feel like I felt it most, I mean I felt it more today than any other days,” Lee said.

“I think just the bogeys that I made I made really soft bogeys, so all of them were really soft. So maybe tomorrow just try and eliminate them or and then try and make as many birdies as I did today.”

For her part, Green scrambled her way around the East Course after hitting less than half the greens in regulation and relying on her short game to keep her in the contest moving forward with more hot weather and severe storms in the forecast.

“I felt like I played a lot worse than the score,” Green said. “So to have even par pretty happy with. I have no idea where that's on the leaderboard. I wasn't really watching too much out there because it's only round one. But I missed a lot of greens and a lot of fairways today so I think that's something I got to fix on the range after this round. Hopefully, yeah, hit more on the next few days.”

Now the field returns to Kasumigaseki Thursday for another day of sweltering heat, another day of hydration, electrolytes and survival, and a clear vision of what’s at stake.