KAWAGOE, Japan – Lexi Thompson had to bring in a team manager the last three holes when her caddie succumbed to the heat. Players walked down sunbaked fairways using umbrellas, some of them occasionally holding a bag of ice on their heads.

Madelene Sagstrom had a hot start of her own Wednesday in women’s golf.

With a tough pitch to 4 feet for par on the final hole, the Swede kept bogeys off her card on a day of searing heat for a 5-under 66, giving her a one-shot lead over top-ranked Nelly Korda of the United States and Aditi Ashok of India.

Extreme heat is nothing new for most of the top players, with an LPGA Tour schedule that includes stops in Singapore and Thailand. This ranked right up there. The heat index topped 100 degrees Fahrenheit (37.8 Celsius), and at that point caddies were allowed to remove their bibs.

“It’s hot, I’m not going to lie. It’s very hot,” Sagstrom said. “But it’s manageable. Most of us have been in Asia, played a lot of golf over here, so we know what to do. You drink a lot of water, you have cooling towels, umbrella, 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.”

No need to explain that to Thompson. She was walking up the 15th fairway when she said her caddie, Jack Fulghum, turned to her and said, “Do I look white to you?”

“I didn’t really notice. But he just didn’t look good,” Thompson said. “I just want him to be healthy, that’s all.”

She had him sit down off the green and brought in Donna Wilkins, who works in player services for the LPGA Tour and is on the staff for Team USA at the Olympics. Thompson birdied three straight holes, closed with a bogey and shot 72.

Sagstrom managed just fine, opening with a 4-foot birdie, using her power to set up a two-putt birdie on the par-5 fifth and navigating a Kasumigaseki course that was drier and faster than it was for the men last week.

Of her five birdies putts, the only one outside 10 feet was a 15-footer on the par-3 10th.

Korda, who reached No. 1 in the world by winning her first major six weeks ago at the KPMG Women’s PGA Championship, overcame a pair of early bogeys with enough birdies to not fall behind, and she eventually worked her way up the leaderboard with a 67.

One of her bogeys was on the par-3 fourth hole, playing 205 yards. She hit 5-iron that never strayed too far from the flag, landed well short of the hole and didn’t stop rolling until she faced a birdie putt from 40 feet. She three-putted.

Korda had talked to a few of the American men about Kasumigaseki and heard all about how soft it was. The opening two rounds of the men’s competition was delayed by storms.

“The greens have definitely firmed up from the men,” he said. “I remember JT (Justin Thomas) was saying how soft it was. And you can kind of see it on the color of the greens. They’re getting a little browner, and there’s some spots that just like ricochet.”

As for the heat? That was more wearisome than worrisome. Korda says she was drinking a bottle of water on each hole, almost to the point of being sick of drinking water.

“You have to keep yourself hydrated and you kind of lose it a little out there,” Korda said. “Like when I was teeing up some balls, I definitely felt a little lightheaded. But kept myself in it.”

Jin Young Ko, who was at No. 1 in the world for nearly two years until Korda replaced her, was among those at 68. Inbee Park, the Olympic gold medalist from Rio de Janeiro in 2016, couldn’t get a putt to fall on the back nine and had to settle for a 69.

Danielle Kang and Sei Young Kim also were at 69.

The surprise was Ashok — or maybe not considering this is the Olympics. She was 18 and fresh out of high school when she made her debut in Rio and opened with a pair of 68s before fading on the weekend.

Now she’s off to another good start, even after having to hit so many hybrids into the par 4s. She was tied for the lead until missing the 18th green to the left and failing to save par.

Ashok remembers the reaction from Rio when she started well, which speaks to how much influence an Olympic golfer can have on a country where cricket is king.

“My social media following just blew up,” Ashok said. “I think a lot of people were trying to figure out what golf was so that they could understand how I was playing and if I had a chance to win a medal.”

She has won three times on the Ladies European Tour since then and became the first player from India on the LPGA Tour. No matter.

“People still remember me as the girl who did well at the Olympics,” she said. “Just knowing that kind of motivates me this week, too.”