"You know, I always just got to do the best that I can," Williams said to the crowd after the match. "I feel so comfortable on this court, in front of everyone here.
"When I step out on the court, I just want to do my best that I can on that particular day. That's really all I can really do."
Since Williams, 40, announced her impending plans to "evolve" from tennis in a first-person essay in Vogue earlier this month, she has been given a farewell tour of sorts, and received standing ovations at both the Canadian Open and the Western & Southern Open.
On Monday night, the sold-out crowd here of nearly 24,000 -- which included a laundry list of A-list celebrities and notables, including former President Bill Clinton, Spike Lee, Lindsey Vonn, Bella Hadid, Rebel Wilson, Vera Wang, Mike Tyson, Dr. Ruth Westheimer, Gladys Knight, Martina Navratilova and even Coco Gauff -- was on its feet before Williams even took the court. After a video narrated by Queen Latifah was shown summarizing her legendary career, Williams was introduced to the crowd as the "Greatest Of All Time" to loud cheers that continued during any break in the action throughout the match.
"The reception was really overwhelming," Williams told reporters. "It was loud and I could feel it in my chest. It was a really good feeling. It's a feeling I'll never forget, so I really -- yeah, that meant a lot to me."
It was Williams' 102nd win at Arthur Ashe Stadium -- the most by any player since it opened in 1997 -- and extended her record for Grand Slam victories by a woman to 366. After the match, Williams was celebrated with an on-court ceremony that featured Gayle King and Billie Jean King, as well as a "Thank you, Serena" video from Oprah Winfrey.
"First of all, thanks, I didn't expect any of this," Williams told the crowd, before crediting the fans for pulling her through to the win.
Gracious in defeat, Kovinic said it was "maybe one opportunity in a lifetime to play against Serena, especially in a night session match on Arthur Ashe," and called it an "experience that I only could think of and dream of maybe in my entire career."
Tickets for Monday's night session became a hot commodity after Williams' announcement in Vogue. According to TickPick, a secondary ticket website, the cost to attend Monday's night session was more expensive than any US Open women's final on record. The average secondary market ticket price was listed at $987 as of Monday morning, according to ticket analytics firm TicketIQ. There were 29,402 fans on the grounds for the night session -- a US Open record.
Even her practice session before the match drew thousands of fans cramming in to sneak a peek of the legend, with rows lined up to catch a glimpse through a mesh fence.
But despite the fanfare and losing three of her four matches since returning at Wimbledon after a yearlong absence, Williams wasn't ready to call it a career just yet. On Monday, wearing a figure-skating-inspired dress originally designed with six layers to represent all six of her US Open titles (but ultimately with four removed due to their weight) and matching diamonds in her hair, Williams glided around the court -- and twirled at the end -- and showed flashes of what has made her one of the all-time greats. She had nine aces and notched 22 winners in the 99-minute match.
Rennae Stubbs, the former player-turned-coach and analyst, has been working with Williams this week in New York. In an interview with ABC prior to the match, Stubbs said Williams was nervous but was still preparing for the match and the tournament with her same trademark intensity.
"The practices have been really hard," Stubbs said on Monday. "She's practiced really, really hard this week. She's practiced with other players, which she's never done in the past. And, you know, she's trying to do everything she possibly can to be at her very best tonight."
Williams will next play No. 2 seed Anett Kontaveit on Wednesday in the second round, in addition to playing doubles alongside sister Venus, whom she called her "rock" on Monday. The two have won 14 major titles together as a team, most recently at Wimbledon in 2016. This marks their first time playing together since the French Open in 2018. The pair is scheduled to open play against Lucie Hradecka and Linda Noskova on Wednesday or Thursday.
Venus, 42, has not revealed any plans to retire but has played sparingly over the past year.
Williams said she was excited to continue her run in singles, but wasn't focused on her next match just yet.
"At this point, honestly, everything is a bonus for me," Williams said. "I mean, I think every opponent is very difficult. I've seen that over the summer. The next one is even more difficult.
"It's good that I was able to get this under my belt. I don't know, I'm just not even thinking about that. I'm just thinking about just this moment. I think it's good for me just to live in the moment now."
Asked if this will definitively be her final tournament, Williams replied with a knowing smile: "Yeah, I've been pretty vague about it, right?"
And then she added: "I'm going to stay vague, because you never know."