After a whirlwind week in Toronto, what's next for Serena Williams?

WATCH: Serena Williams says goodbye to tennis in Toronto with must-see sendoff

Serena Williams only played two matches in Toronto this week. Considering that she’s won the Ontario tournament three times, that was hardly the usual number. But certainly, they were eventful matches, marked most of all by news breaking on Tuesday that Williams is planning to retire, in all likelihood, after this year’s US Open.

A Google search conducted this Thursday morning for the phrase, “Serena Williams to retire” generated 64.5 million results. They touch on a wide range of topics, addressing so many of the ways Williams has made a mark on the world—not just in sports, but in society.

One story that struck me quite powerfully was written by Louisa Thomas of the New Yorker. “She cradles the ball delicately,” wrote Thomas. “Her toss does not drift under pressure, nor drop when she’s tight. It takes a lot of training to achieve that kind of consistency, no matter the situation, no matter the choice of serve. It involves a mastery that is not only mechanical but psychological.”

The toss indeed is the frequently overlooked asset in a first-rate serve. But study those players with great deliveries closely—Alice Marble, Pancho Gonzales, John Newcombe, Martina Navratilova, Pete Sampras, Serena—and you will see how the toss is at once feathery soft and repeatedly accurate. A great toss permits tremendous disguise and, as the motion continues, lets the server generate sustainable power and pinpoint accuracy.

In her opening match versus Nuria Parrizas Diaz, Williams served seven aces and fought off seven of eight break points to win, 6-3, 6-4, and earn her first singles victory in 430 days.

“I mean it's just one win, you know, it takes a lot,” she said following the match. “But I was happy, like I said, to have a win. It's been a very long time. I forgot what it felt like.”

Besides first-rate serving, Williams also struck many excellent groundstrokes in that match. And even though she lost in the next round to Belinda Bencic, there too, Williams showed impressive signs, even as she simultaneously competed for the first time since announcing her impending retirement.

“Yeah, it was a lot of emotions,” Williams said in an on-court interview conducted just after the match. “Obviously I love playing here. I've always loved playing here. And, yeah, I wish I could have played better, but Belinda played so well today.”

Next comes Cincinnati, followed by the surely grand farewell at the US Open. Over the course of winning there six times—in her teens, 20s, and 30s—Williams has built a tremendous New York legacy.

Over the course of those title runs, the Serena match I find most compelling came, naturally, against her toughest rival, Venus. It happened in the 2008 quarterfinals. On a sultry New York evening, over the course of two hours and 25 minutes, Serena fought off two set points in the first set and eight in the second to earn a 7-6 (6), 7-6 (7) victory.

“I can’t say I’m disappointed,” Serena said afterwards. “But I can’t believe I won.”

Following that match, Williams beat a pair of players who’d each hold the No. 1 ranking—Dinara Safina and Jelena Jankovic—to win her third US Open title. Her next three wins came in the form of a dazzling three-peat, earned from 2012-14.

So what can we expect from Williams this year in New York? As the event unfolds, the emotions for all—Serena, her family, friends, fans and peers—will be exceptionally heartfelt. The cheers will likely be louder than any ever heard inside Arthur Ashe Stadium. And the tennis will be inspired. My biggest hope for Williams is that she remains healthy and able to play her best possible tennis for the entire tournament.

“Mentally I feel I'm getting there,” Williams said in Toronto. “I'm not where I normally am and I'm not where I want to be. But I think any match that I play, whether I win or lose, it helps me get there mentally. Because I haven't played a lot in the last year, two years. So I think that that really helps me. Physically I feel much better in practice, it's just like getting that to the court.

“But literally I'm the kind of person who it just takes one or two things and then it clicks. So I'm just waiting on that to click.”