Raducanu, who was virtually unknown even in Britain at the start of the year, will become the youngest Slam finalist in 17 years after beating Greek 17th seed Maria Sakkari 6-1, 6-4 in a nerveless display.

"I'm in the final and I can't actually believe it," Raducanu said.

Fernandez, a 73rd-ranked left-hander, beat second seed Aryna Sabalenka of Belarus 7-6 (7/3), 4-6, 6-4, for her third Open win over a top-five rival, a feat not seen at a Slam since Serena Williams at Wimbledon in 2012.

"Now I can say I've done a pretty good job of achieving my dreams," Fernandez said.

The teen prodigies will meet Saturday at Arthur Ashe Stadium, where one of them will claim her first Grand Slam title.

"Is there any expectation?" Raducanu said. "I'm a qualifier so technically on paper there's no pressure on me."

It's the first Slam final between teens since 17-year-old Williams beat 18-year-old Martina Hingis at the 1999 US Open, and just the eighth all-teen Slam final in the Open era (since 1968).

"I just want to play a final," Fernandez said. "I'm going to enjoy my victory and worry about it tomorrow."

Raducanu is the youngest Slam finalist since 17-year-old Maria Sharapova won at Wimbledon in 2004.

She became only the second woman ranked outside the top 100 to reach a US Open final after unranked Kim Clijsters came out of retirement and won the 2009 US Open.

"Today I wasn't thinking about anyone else except for myself," Raducanu said.

Raducanu is trying to become the first British woman to win a Grand Slam title since Virginia Wade at Wimbledon in 1977 and the first British woman to win the US Open since Wade in 1968.

Wade and British legend Tim Henman were watching.

"Tim is such a big inspiration," said Raducanu. "He has been helping me, telling me take one point at a time. You have to stay in the moment and can't get ahead of yourself."

Fernandez, who turned 19 on Monday, had earlier ousted defending champion Naomi Osaka and fifth-seeded Elina Svitolina before Sabalenka, 23, become her third top-five victim.

"I had opportunities but I didn't use them in the key moments," Sabalenka said. "I didn't play well. She deserved this win."

Raducanu could become the first US Open champion not to lose a set since Serena Williams in 2014.

Raducanu saved three break points in her opening service game then broke to lead 2-0. Sakkari double faulted to hand the teen a 4-0 edge and she took the first set in 36 minutes, aided by Sakkari's 17 unforced errors.

An errant Sakkari forehand in the third game of the second set handed Raducanu the only break she needed as she advanced after 84 minutes on an overhead smash.

"I played some of my best tennis to date," Raducanu said. "I knew I'd have to be super aggressive and execute and I'm just really happy with today's performance."

'Years of work'

Fernandez, never deeper than the third round in six prior Slam starts, showed the mental toughness preached by her father-coach Jorge in the tie-breaker.

Sabalenka netted a forehand with a wide-open court to hand Fernandez a 3-2 edge. The teen never trailed after that, winning the last four points to claim the first set in 53 minutes.

"That's years and years of work and tears and blood and sacrifice," said Fernandez of her mental fortitude.

The Ashe stadium music director played the Eric Clapton song "Layla" as the crowd roared when she took the set.

"I have no idea (how I won)," said Fernandez. "I'd say it's thanks to the New York crowd. They helped me. They cheered for me. They never gave up."

Fernandez sent a forehand long to surrender a break in the ninth game and Sabalenka held at love to take the second set.

In the third, Fernandez held to 5-4 and Sabalenka crumbled with the match on the line, issuing back-to-back double faults to 0-40 and sending a forehand long — her 52nd unforced error — to fall after two hours and 21 minutes.

"I don't know how I got that last point in but I'm glad it was and I'm glad I'm in the finals," Fernandez said.