Tennis is so much of a mental game. That's why Bianca Andreescu shines

"Right now!"

That's what 19-year-old Bianca Andreescu yelled as she turned to the crowd after coming back to tie the second set of her match against Switzerland's Belinda Bencic during Thursday's U.S. Open semi final.

And while Andreescu might have been talking about the match one she would win in two sets, 7-6, 7-5, coming from behind in both she might have well been talking about her moment in tennis, which is happening now, as she emerges as one of the greatest in the world.

The Mississauga, Ont. teen will face off against Serena Williams in the finals Saturday, to mark an incredible achievement for Canadians and teenagers alike. But unlike most teenagers, what makes Andreescu such an exceptional athlete is not simply her physical gifts, but also her mental strength.

Yes, she has a powerful forehand, a threatening serve and a keen ability to mix up power, spin, and drop shots. But while most young players get by based on their elite athleticism and raw talent, Andreescu has made it to the final of the U.S. Open in large part due to her ability to thrive under pressure and get better as the games go along.

Tennis is a unique sport in that it is completely on the player to figure out the game (and the opponent) as it progresses. In almost every other sport, the coaches (in some sports, a bench full of them) are there to help athletes sort through the tactical parts of the game.

Tennis players do have coaches, but it's against the rules to have any communication with a coach during the match. In fact, players will be fined for it.

Tennis is a strategic sport centred on understanding your opponent, as well as on using an array of different tactics and moves to be as unpredictable as possible. And you have to rely on your eyes and your head alone.

What's more, some matches go on for hours; Andreescu vs. Bencic lasted over two hours and didn't even have a third set. And the more tired any athlete becomes, the harder it is to remain focused.

All of that is to say it takes extreme mental strength to become a professional tennis player, and even more for it to be your calling card. And try being a teenager on top of that.

Andreescu clearly thrives under pressure, demonstrating a rare calm for such a relatively new player. She credits meditation and visualization for keeping her focused in the moment. And it works: she routinely seems to find one of those unreturnable, over-100-mph serves when she is in a hole, or energy for an incredible rally after a moment of looking down and out which she found during the second set of her match with Bencic, eventually taking the crucial point and game.

This U.S. Open run in particular has showcased her ability to get better as the games go along, and thus figure out her opponents better (and faster) than they can figure out her. She battled back from being down a set against Belgium's Elise Mertens in the quarter final, before coming back from a 2-5 hole against Bencic in the second set of the semi final, winning both matches.

Andreescu's game is so advanced relative to her age that some have already compared her to her U.S. Open final opponent, Serena Williams. Williams, however, was a much more well-known prospect than Andreescu and won her first Slam as a 17-year-old at the 1999 U.S. Open. That was the day Williams became a superstar.

No doubt most of the American crowd watching the championship game will be rooting for Williams, who has a chance to equal Australian Margaret Court's record of 24 singles Grand Slam titles. Canada, however, will be rooting for our own, watching anxiously as Andreescu goes from rising star to superstar and follows in the footsteps of the best to ever do it.

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