Teen titans Leylah Fernandez, ranked 73rd, and Emma Raducanu, the world No 150, are both one victory away from reaching their first Grand Slam final at the US Open.

Even in the gloriously unpredictable era of women’s tennis, this is an unexpected twist. Both teens have promising game styles and are full of potential, but it’s almost unbelievable how quickly they have developed it and broken through in front of a packed stadium in New York.

Britain’s 18-year-old Raducanu is only the fourth qualifier to reach the semi-finals at any Slam and the first at US Open. Fernandez, ousted former champions Naomi Osaka and Angelique Kerber before turning 19 in New York.

Left-hander Fernandez will face second-seeded Aryna Sabalenka, who has matched her deepest Slam run from July at Wimbledon, while Raducanu faces Greek 17th seed Maria Sakkari, who matched her best Slam run from French Open. But despite their opponents being more experienced, the hope for an all-teen Grand Slam final is alive and with good reason.

Raducanu rises from the cauldron

Raducanu is yet to drop a set at US Open, or play a tiebreak, having made the main draw after three rounds of qualifying. Olympic champion Belinda Bencic was the first seed she played in New York, in the quarter-final, and she made light work of that too.

But what makes the world No 150’s run ever more remarkable is that fact that she made her WTA debut in June and Grand Slam debut only in July, with a run to the fourth round at Wimbledon as a wildcard that really put the spotlight on her. She had to forfeit the match, retiring due to breathing problems, that suddenly made her the target of unsavoury comments from prominent people in the sports world.

John McEnroe and Kevin Pietersen were among the people who suggested that the teenager was unable to handle the pressure of the big stage. But Raducanu has more than proved the doubters wrong as she not only qualified for her first Major main draw, but has also reached the final four with a fearless display at the biggest stage.

Raducanu became the youngest US Open women’s semi-finalist since Maria Sharapova in 2005. Only unranked Billie Jean King in 1979 and Kim Clijsters in her 2009 title run have reached a US Open semi-final with a lower ranking than the current world No 150 Raducanu, who is set to become the new British No 1.

RD128: bt Stefanie Voegele (SUI) 6-2, 6-3

RD64: bt Zhang Shuai (CHN) 6-2, 6-4

RD32: bt Sara Sorribes Tormo (ESP) 6-0, 6-1

RD16: bt Shelby Rogers (USA) 6-2, 6-1

QF: bt Belinda Bencic (SUI x11) 6-3, 6-4

Given her low rank, she was barely able to play last year due to the pandemic. In fact, when she got the Wimbledon wildcard and subsequently played the second week, she joked about having to do laundry because she didn’t come equipped with enough kits to make a deep run.

Raducanu, the Canadian-born daughter of a Chinese mother and Romanian father, 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.

Fearless Fernandez

Leylah Fernandez, who turned 19 on Monday, has virtually grown up at the US Open beating not one but two former champions as an 18-year-old. Her self-belief and shot-making have been tested under the most pressurised of situations but she has come through with such poise, it’s hard to believe she is ranked under 70. Indeed, she is now the youngest player to defeat two top-5 players at the same Grand Slam since 17-year-old Serena Williams at US Open in 1999.

In her third-round match, Naomi Osaka, the defending champion and four-time Grand Slam winner, was serving for the match but it was the teen who caused a stunning upset with a hard-fought 5-7, 7-6 (7), 6-4 win.

In the fourth round, she fought past 16th seed and three-time Grand Slam champion Angelique Kerber 4-6, 7-6 (5), 6-2 in another three-setter.

Her quarter-final was another three-set battle against Olympic bronze medallist Elina Svitolina, which she won 6-3, 3-6, 7-6 (5).

Three straight matches against top-seeded veterans, three tiebreaks and three big wins mean the world No 73 heads into the semi-final with rare experience and poise.

Road to semi-final

RD128: bt Ana Konjuh (CRO) 7-6 (7/3), 6-2

RD64: bt Kaia Kanepi (EST) 7-5, 7-5

RD32: bt Naomi Osaka (JPN x3) 5-7, 7-6 (7/2), 6-4

RD16: bt Angelique Kerber (GER x16) 4-6, 7-6 (7/5), 6-2

QF: bt Elina Svitolina (UKR x5) 6-3, 3-6, 7-6 (7/5)

Fernandez, the daughter of an Ecuadoran father and Filipino-Canadian mother, won her first WTA title in March at Monterrey and her best Grand Slam run before this was the third round at French Open last year. She has a career-high singles ranking of world No 66, achieved in June, and is set to break into the top 30 at least.

Fernandez was cut from a Canadian youth tennis development program. Her father Jorge, an Ecuadorian soccer player, became her coach in a sport he knew almost nothing about. Fernandez, whose mother is of Filipino heritage, is also guided by pro coach Romain Deridder. Her father is at home but still sending in plans for matches and the combination seems to have worked wonders for the Canadian.

Can she emulate compatriot Bianca Andreescu and go all the way? Given her track record in the last week, it cannot be counted out.