Serena Williams has a Saturday night date with destiny — and her emotions.

This wasn’t just a U.S. Open semifinal victory — Serena’s 101st victory in Flushing. This was a demolition and a demoralizer to fifth-seed Elina Svitolina before an Arthur Ashe Stadium crowd that couldn’t get enough of Williams’ raw power.

The final count was 6-3, 6-1 but this was decided in the first two games. Any chance for Svitolina to get into Williams’ head evaporated after she squandered two break points on Serena’s serve to open the match. Then on Svitolina’s next serve, the Ukrainian got up 40-0, blew the game and fell behind 3-0.

That was all Williams needed to get into the night and play maybe her best tennis since becoming a mother.

Serena received a standing ovation after the first set. She was ferocious, taking out all her angst on the yellow ball. She zoomed about the court like she was 27 and not a 37-year-old mother of a 2-year-old.

“That’s why she is who she is,’’ Svitolina said. “You are playing in front of the best tennis player in the world. If you don’t take it, she just grabs it and there’s no chance to take it back. In the important moments, she always step up, always brings her best game.”

Not always. We can think of several other times in Flushing when she didn’t step up her tennis or her mental game. There were no tantrums, but the worst was the 2015 Open semifinals when she got outsmarted by knuckleballer Roberta Vinci when on track to win the Grand Slam, a sweep of all four majors in a calendar year.

And of course one year ago, Williams was one victory away from the best history you can make in this sport — tying Australian Margaret Court for a record 24 Grand Slam titles.

Serena let it all slip away against Naomi Osaka, melted down in epic fashion after getting a warning/code violation from chair umpire Carlos Ramos because her coach gave her hand signals.

“I think she’s more relaxed this year, feels less pressure,’’ said one person close to the family.

Williams, who saw a therapist after last year’s meltdown, confirmed “I’ve been way more chill.”

Again, she is one win away again from equaling Court, who will not be in attendance. According to industry sources, the Open refuses to invite Court to Flushing Meadows because of public remarks in 2017 she made against the LGBT community.

Billie Jean King supported Serena’s relentless haranguing of Ramos last year and is pulling heavily for history Saturday in the finals.

“It’ll be great if she won this and went on to Australia and broke it,’’ King, who is gay, said on TV. “That’s my prayer.”

Williams admits it has been challenge to be “a full-time mom’’ while chasing Court. There’s been zero titles since she gave birth two years ago.

“My day off isn’t a day off,’’ Williams said of motherhood.

Three times, she’s been one win away from 24 and failed to deliver.

“I would definitely still be playing if I already passed it,’’ Williams said Thursday. “I’ve had so many chances to pass it and to have a lot more. It’s cool.’’

Despite the 34 winners, so many of them spectacularly angled bullets, she claimed this “wasn’t my best tennis.’’

Late in the second set, it didn’t look that way as Serena pulled stuff out of her comfort zone. She did some serve and volley.

“Don’t expect that again,’’ Serena said.

In the final game, Serena pulled Svitolina in on a drop shot and passed her with a touch volley. A point later, Williams sprinted like a deer for a drop shot and smacked a crosscourt winner, sending the fans into another frenzy.

Williams was in the interview room when Belinda Benciic and Biana Andreescu were battling in the first set of the second semifinal. She will face Andreescu in the final Saturday. Williams spoke about the “five eras’’ she’s grinded through. Of this one, she said, “There’s no easy match.’’

There will be no Ramos, banned from Serena matches, on Saturday night. It should be an easy roll to history if Serena lets it be.