NEW YORK, Sept 10 (Reuters) - Leylah Fernandez and Emma Raducanu will clash in one of the most improbable U.S. Open finals on Saturday, the teenagers" fearless tennis bringing them to the cusp of becoming the sport"s newest major champion. Their title clash under the lights at the Arthur Ashe Stadium will be the first major final in the Open Era in either the men"s and women"s game to feature two unseeded players. Canadian Fernandez, who turned 19 this week, was ranked 73rd coming into the hardcourt Grand Slam while 18-year-old Briton Raducanu was 150th in the women"s rankings. But with no burden of expectation on their shoulders, the duo have showcased a brand of fearless tennis at Flushing Meadows that has endeared them to the fans and helped them chart a path to the showpiece match. "They are both young. They play fearless. They have nothing to lose playing against us," said Greek Maria Sakkari, who bowed out in the semi-finals with a straight-sets loss to qualifier Raducanu. "I have to give credit to both of them, both of the young girls, that they take their chances. They"re out there fighting for that title. Very well done to both for getting here." Saturday"s final will be the first tour-level meeting between them but the pair previously clashed in the second round of the 2018 Wimbledon juniors when Raducanu won 6-2 6-4. It will also mark the first Grand Slam final to be contested by two teenagers since Serena Williams and Martina Hingis met in the 1999 U.S. Open title clash. Sep 9, 2021; Flushing, NY, USA; Emma Raducanu of Great Britain waves to the crowd after her match against Maria Sakkari of Greece (not pictured) on day eleven of the 2021 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Robert Deutsch-USA TODAY Sports Sep 9, 2021; Flushing, NY, USA; Leylah Fernandez of Canada celebrates after her match against Aryna Sabalenka of Belarus (not pictured) on day eleven of the 2021 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Danielle Parhizkaran-USA TODAY Sports Sep 9, 2021; Flushing, NY, USA; Emma Raducanu of Great Britain waves to the crowd after her match against Maria Sakkari of Greece (not pictured) on day eleven of the 2021 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Robert Deutsch-USA TODAY Sports 1/2 Sep 9, 2021; Flushing, NY, USA; Leylah Fernandez of Canada celebrates after her match against Aryna Sabalenka of Belarus (not pictured) on day eleven of the 2021 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Danielle Parhizkaran-USA TODAY Sports NATURAL GIFT "With Raducanu and with Leylah Fernandez, they know how to win. They know how to stay calm in the most important moments," said Eurosport tennis expert and seven-time Grand Slam champion Mats Wilander. "They have a natural gift of not panicking, and that"s amazing. I can"t even explain it." The first British woman to reach a major final since Virginia Wade won Wimbledon in 1977, Raducanu can jump to 24th in the rankings with her first title while the left-handed Fernandez can make her top 20 debut by winning the U.S. Open. The Briton has, however, had a less arduous path to the final. She has not dropped a set in her nine matches at Flushing Meadows to become the first qualifier - in men"s and women"s tennis - to reach a major final. In contrast, Fernandez has had to conjure every ounce of her fighting spirit to move past the heavyweights of women"s tennis and be in a position to give Canada its second U.S. Open women"s title in three years after Bianca Andreescu"s 2019 triumph. The Canadian had to defeat three top-five players and a multiple major winner in her last four matches - all in three sets - to book her spot in the final. "Raducanu and Fernandez play very similar in a way. If Fernandez was right-handed you wouldn"t see much difference in their styles. They are pretty close in how they play," added Wilander.