Emma Raducanu and Leylah Fernandez are so similar in numerous ways: They possess enviable quickness and anticipation. They take balls low to the bottom and redirect them with ease. They love the large moment. they do not care what proportion better-known or more successful opponents are. There’s more. They’re both teenagers. They’re both unseeded at the U.S. Open. They’re both …

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 therefore the crowd. What often happens next, after …

– Leylah Fernandez may be a self-described “happy-go-lucky girl” having the time of her life at Flushing Meadows, raising her fists, pumping her arms, and riling up crowds while beating two past US Open champions to succeed in her first slam quarterfinal. A day before her 19th birthday, the unseeded left-hander from Canada grabbed the last five games to eliminate …