After being postponed by three months due to the coronavirus pandemic, the third major championship of the year was played largely in silence with no crowd in attendance at the Aronimink Golf Club.
But that didn’t seem to bother the Korean 27-year-old one bit, as she hit 29 on the front nine to match the tournament record on Friday, on her way to a record final round and five-stroke win on Sunday (11th October).
Rio 2016 Olympic champion Inbee Park finished in second-place, while Nasa Hataoka and Carlota Ciganda tied for third at 7 under.
Below, we take a look at some of the main talking points in the aftermath of the event in Pennsylvania.
Kim Sei-young finally joins the major club
Before the tournament, Kim had the unenviable record of being the most successful golfer to have not won a major, with 10 LPGA wins.
The Rio 2016 Olympian had come close to winning this tournament before, having finished as runner-up at the 2015 Women's PGA Championship and joint-second at the 2018 championship.
But these statistics were soon forgotten as the third-degree blackbelt in Taekwondo finished on 14-under overall to take the first-place prize of $645,000.
"This golf course is really challenging," Kim told reporters after. "I tried to keep the focus on my job. It was really tough.
"Sometimes I'm shaking my head and my legs were shaking but I was able to keep my focus and I was able to reach my big goal, so I'm very happy about that."
A more enviable statistic is that Kim now has at least one win in every LPGA Tour season since 2015.
Inbee park remains a pillar of consistency
The 32-year-old hit a bogey-free 65 on Sunday, but while her round was almost flawless, she lost ground on the day thanks to the genius of her rival.
There was also something of a role reversal in the 2020 PGA Golf Championship, five years after Park beat Kim by five shots at Westchester Country Club.
"Sei-young was just really untouchable," the seven-time major winner said magnanimously after Kim's win in Pennsylvania.
"It was just so hard to believe that she never won a major before because it felt like she won a few.”
Nasa Hataoka coming good ahead of Tokyo Olympics
Nasa Hataoka of Japan shot a final-round 64 to seal third-equal place in an interesting sub-plot to the championship, less than a year away to the Tokyo 2020 Olympics.
The 21-year-old had one particularly brilliant moment to savor, when she holed a 188-yard five-iron to eagle the first hole.
Hataoka is yet to win her first major, but felt that she had taken ‘one more step’ towards that goal in Pennsylvania.
"I felt like I had no choice but to play aggressive golf and not give up until the end. It was big that I was able to get through the round without a bogey," Hataoka told media after.
Rio 2016 saw golf restored to the Olympic programme for the first time since 1904, and Hataoka’s good showing will greatly encourage the Tokyo 2020 Games hosts.
Women’s golf more competitive than ever
Kim is not the only new winner in recent times in women's golf, with nine of the last 10 major champions also being first-time winners.
The Korean joins Sophia Popov (Women's British Open) and Mirim Lee (ANA Inspiration) as this year's major champions.
With the US Open due to take place this December, the final major of the year may yet add another name to that list.