HOUSTON — A Lim Kim ran into trouble after she birdied the final three holes for a three-under 67 that catapulted her to victory on Monday in the 75th United States Women’s Open.

As Kim sat in front of a large-screen TV in the Champions Club players’ dining area watching the competitors with a chance to catch her finish, she fumbled her phone, which was vibrating with messages from family members and friends back home in South Korea who had stayed up all night to watch her round.

The phone fell to the bottom of her golf bag and Kim removed all her clubs to retrieve it while, one after the other, her challengers fell by the wayside.

Hinako Shibuno of Japan, the 54-hole leader, couldn’t catch Kim. Shibuno had held a one-stroke lead after Sunday’s final round was postponed by inclement weather, but bogeyed the penultimate hole Monday and finished fourth at one-under with a closing 74.

Kim’s compatriots, Inbee Park and Jin Young Ko, the women’s world No. 1, both carded the second-lowest score of the day, a 68. Ko’s round included birdies on two of the last three holes, to come up one stroke short of Kim at two-under 282.

The American Amy Olson, who took the solo lead on the back nine in her bid to gain both her first L.P.G.A. victory and major win, tied for second with Ko. Her title hopes were dashed with a bogey on the par-3 16th, the same hole she had aced in the first round.

Olson, 28, playing after the sudden death Saturday night of her father-in-law from a heart attack, closed with a birdie for a one-over 72. Olson sang bars from Josh Groban’s song “You Raise Me Up” to mask her grief.

Kim, 25, meantime, provided a perhaps fitting portrait of a champion of a tournament that was delayed six months because of the coronavirus pandemic. She won wearing a face covering on and off the golf course while establishing herself as the class of a field in which only four players bettered par.

“I’m OK to get positive tests for Covid-19,” Kim said through an interpreter, “but I don’t want to affect other people — players, a caddie that’s playing within the group — so that’s the reason I wear the mask throughout the round.”

Because it took place so late in the year, the U.S. Women’s Open had the rare chance to showcase its players in America without sharing the stage with a 72-hole PGA Tour event or other U.S.-based events in a schedule that is usually packed during its normal late spring date.

The United States Golf Association embraced the hashtag #WomenWorthWatching and a few players from the PGA Tour followed suit, much to the bemusement of the current generation of Asian L.P.G.A. stars who have never lacked for attention at home. That Monday’s final round was televised live in South Korea in the middle of the night says a lot about the popularity of women’s golf in a country where the best female golfers are more popular than the men who play on the PGA Tour.

“Yeah, in Korea we get definitely a lot of attention and maybe we don’t need that phrase,” said Park, 32, a former world No. 1 whose final-round 68 vaulted her into a three-way tie for sixth at two-over 286.

Park, who has 20 L.P.G.A. titles, including seven majors, said she gets recognized walking the streets in South Korea or paying the operator at a tollbooth while driving.

In Thailand, Moriya Jutanugarn, 26, and her younger sister, Ariya, also command attention, since Ariya was the subject last year of a biopic that also included Moriya. On Monday, Moriya closed with a 74 to finish tied for sixth, one stroke ahead of Ariya, a former world No. 1.

In Japan, Shibuno saw her life change rapidly after she won last year’s Women’s British Open in her first professional tournament outside her homeland. “I turned from a normal person to a celebrity overnight,” Shibuno said through an interpreter.

She added, “Once I became a celebrity, and celebrity status, it makes it difficult to be myself.”

This was Kim’s U.S. debut and with the win she becomes the latest in a long line of Korean players to take women’s golf by storm. Since turning professional as a teenager in 2013, Kim has won twice on her home tour and become known for her length.

Kim, who is not a member of the L.P.G.A., earned $1 million for the victory. She also is eligible for a two-year tour membership, but said she is not sure if she will join in 2021. The decision would likely require several major disruptions to her life.

“I just need some more time to think about it,” Kim said.

Golf looked like the easy part for Kim, who took several deep breaths during her news conference to calm herself. “Once I go back home,” she said, “I’ll think about it and see.”