NEW YORK — Emma Raducanu and Leylah Fernandez are so similar in so many ways: They possess enviable quickness and anticipation. They take balls low to the ground and redirect them with ease. They don't care how much better-known or more successful opponents are. They love the big moment. There's more. They're both teenagers. They're both unseeded at the US Open. They're both getting loud backing from the crowds. And now, remarkably, they're both Grand Slam finalists.

Raducanu, an 18-year-old from Britain who is ranked 150th, and Fernandez, a 19-year-old from Canada who is ranked 73rd, took wildly different paths to the championship match at Flushing Meadows on Thursday night. They'll be back in Arthur Ashe Stadium on Saturday for the first major final between two teens since the 1999 US Open, when Serena Williams, 17, defeated Martina Hingis, 18.

Raducanu became the first qualifier to reach a Grand Slam final in the professional era by overwhelming 17th-seeded Maria Sakkari 6-1, 6-4. Appearing in just her second major tournament, Raducanu won all 18 sets she has played during three matches in qualifying rounds and six in the main draw. "I've just been taking care of each day," Raducanu said, "and before you know it, three weeks later, I'm in the final and I can't believe it." Who can? Not Raducanu, who originally bought a plane ticket to leave New York after qualifying ended, figuring that might be the end of her stay.

Quickly, she led Sakkari 5-0 and nothing really changed from there. Sakkari earned seven break points in that span; Raducanu got three. The difference? Sakkari couldn't convert any; Raducanu took advantage of two chances — or, better, accepted her opponent's generosity on two of them, once on a netted backhand, once on a double-fault.

By the end, Raducanu made just 17 unforced errors to Sakkari's 33 and now is the youngest Slam finalist since Maria Sharapova won Wimbledon at age 17 in 2004. Fernandez isn't much older — her birthday was Monday — and she made it through a semifinal filled with momentum swings to edge No. 2 Aryna Sabalenka 7-6 (3), 4-6, 6-4.

"They are both young. They play fearless," Sakkari said about Raducanu and Fernandez. "They have nothing to lose playing against us." Raducanu agreed with that assessment, saying: "Being young, there is an element of you do play completely free." Sakkari is 26, Sabalenka 23. Each recently made her debut in a Grand Slam semifinal: Sakkari lost in that round at the French Open in June, Sabalenka at Wimbledon in July.