'Trusting myself': Leylah Fernandez, 19, reaches US Open SF

New York: When Leylah Fernandez wins a pivotal point at the U.S. Open - and she's won enough of them to become the tournament's youngest semifinalist since Maria Sharapova in 2005 - the teenager with the exciting game and enthusiasm to match raises her right fist or windmills her arms, firing up herself and the crowd.

What often happens next, after good points or bad, is just as important to the success of the unseeded Canadian left-hander with the quick reflexes: She'll turn her back to the court and her opponent, face the wall behind the baseline for a few moments, gather herself and repeat whatever that day's mantra of choice is. During Tuesday's 6-3, 3-6, 7-6 (5) victory against No. 5 seed Elina Svitolina in Arthur Ashe Stadium, which followed wins over past U.S. Open champions and former No. 1s Naomi Osaka and Angelique Kerber, Fernandez focused on self-belief.