Serena Williams won her first title on the women’s tour on Feb. 28, 1999.

More than two decades ago. She was 17.

Sunday afternoon, the greatest women’s player ever will be going for her No. 73 and a fourth Rogers Cup championship — against Mississauga-born teenager Bianca Andreescu.

They’ve never met before.

But the 23-time Grand Slam champion had to work for it, digging out from a one-set-down hole to dispatch qualifier-on-a-roll Marie Bouzkova 1-6, 6-3, 6-3 at the Aviva Centre.

Williams is beloved in Toronto. Her just-turned-21 opponent, however, made a whole lot of new fans over the past week, coming out of nowhere to knock off three Slam titleholders: Sloane Stephens, Jelena Ostapenko and Simona Halep, although the Romanian — former No. 1 — succumbed to an ankle injury in their quarterfinal on Friday. But Bouzkova was up a set at the time.

The Czech Republic native — a business student at East Indiana University now — played seven matches in a row, Saturday to Saturday and hadn’t dropped a set before running into the ferociously unyielding Williams. And through the opening frame, Bouzkova had Williams looking stunned, like a deer in the headlights. This despite the fact Bouzkova had only seven winners. While Williams racked up 14 unforced errors.

Except, of course, Williams is no naif and far from getting rattled by a challenger with zero tour titles, No. 91 in the world — albeit her ranking will soar shortly — and a tennis resume onion-paper thin.

In her eighth Rogers Cup semi, Williams took the measure of her young opponent and made quick adjustments after the first set, thwarting the counterpunching Bouzkova’s energetic defence by hitting around her whenever possible, staying patient. That forced the Czech to run miles and while she still managed to get to the ball more often than not, it became increasingly difficult to return with efficiency or cunning.

“I needed to be more consistent and not make so many errors,” said Williams afterwards. “Mentally be ready to hit 1,000 balls if I needed to. I just had to play a different game.”

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She has so many — games. It doesn’t have to be about one or two particular aspects — or the aces, of which she put up 11, including a pair constructing match point.

“That was really important for me, to change it up, move it around, not be so predictable. It’s a good lesson for me in the future as well.”

It had been a long time since Williams has played five matches in five days — which it will be on Sunday. Actually not since Rome 2016. “We’ll see what happens. It’s definitely different for me. I knew coming into the tournament and they told me Wednesday (first match). I was like: Oh my God, are you sure?

“I definitely feel more grooved in. I feel good still. I’ve been doing a lot of training, all the right things.”

And, like Andreescu, she’s healthy and fit again. Both had been plagued by injury in the first half of the season — knee for Williams, shoulder for the Canadian.

Williams revealed that she’s wanted to face Andreescu for a while, at least since the teenager first came across her radar. That was in January when Andreescu beat Venus Williams in the quarterfinals of the Auckland Open.

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“When you’re that young, everything is so fun … everything is new and everything’s a different challenge. There’s not a ton of pressure.”

Naturally, Williams expects the final crowd to be partisan, putting aside their historical fondness for the American veteran.

“The crowd will obviously be for her. I would too. But it’s really not about that. It’s about going out there and playing great tennis. Luckily I’ve had some tough crowds in my career. Hopefully I’ll be used to it.”

In a final humorous aside — and Williams has been in a jokey mood all week — Williams disclosed to reporters at her post-game press conference that her mind often wanders during a match.

“At one point I was thinking about my bra. And I’m like: My God Serena, are you kidding me?”

Rosie DiManno is a columnist based in Toronto covering sports and current affairs. Follow her on Twitter: @rdimanno

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