The 18-year-old showed poise and composure to come through two tough, grueling sets and beat his more experienced opponent 6-3, 6-4.
“I didn’t expect to be here at all,” Radukanu told reporters after his victory. “I mean, I think my flights were booked at the end of qualifying, so that’s a good problem.
“I’m really enjoying the experience. On the court today, I was saying to myself: ‘This might be the last time you play on Ash, so just go for it and enjoy everything.’
“I didn’t compete for 18 months, but here I am, and it just shows that if you believe in yourself, anything is possible.”
Remarkably, Radukanu is yet to drop a set in his eight games at the US Open – five in the main draw and three in qualifying – and is the first qualifier in history to reach the last four at Flushing Meadows.
She will now face 17th seed Maria Sakkari for a place in the final on Saturday, which will take her more than 24 hours to recover.
When asked how she maintains such composure in moments of high pressure, Radukanu credited the lessons she learned from her parents when she grew up.
Radukanu then jokingly said that they were “ghosting” him when he tried to contact them the day before his victory.
“I think that peace and mental strength definitely comes from my upbringing,” she said.
“I think both my parents definitely inspired me to have a positive outlook on the court from a very young age, because yeah, when I was younger, it certainly wasn’t perfect if I had any. It was kind of bad attitude.
“So from a young age, I’ve definitely learned this, and it’s followed me so far.
“When you’re serving a match on such a big stage, going into your first semi-final of a slam, you definitely need a sense of calm to get past that moment, especially I love – was 30 years old, and just to reset and focus on what i could control.
“I knew exactly what patterns I was going to play and yes, I was just very focused and at the moment. Don’t get ahead of yourself. “
Canada’s Leyla Fernandez defeated Elina Svitolina on Tuesday to make Radukanu the second teenager to reach the semi-finals of this year’s US Open.
‘Show the world all its virtues’
Patrick Mouratoglu is perhaps best known for coaching Serena Williams, but he also knows a thing or two about nurturing emerging talent.
Mouratoglu says Radukanu’s deep run at both Wimbledon and the US Open should get tennis fans, especially in Great Britain, excited about his future potential.
“I’m sure you are [British fans] Very excited about Emma,” Mortoglu told CNN Sport. “Me too, if I were British – and even though I’m not British, I think it’s very exciting. He’s a great, great young player who has everything but a sudden emergence at Wimbledon.
“We knew him because we had been in the tennis industry for many years. We knew he had talent, we knew he had potential, but he’s really suddenly able to show the world all his qualities and see him.” “It’s always good.
“I also love seeing the faces of those young players to see what they are capable of achieving and so it’s great to see this raw joy.”
As with any budding talent on tour, Mouratoglu says that the weight of hope will eventually catch on with Radukanu and that her future success will be determined by how she deals with it.
However, she believes that the freedom she has been playing as a young star, with no pressure on her shoulders, has helped Radukanu exceed her expectations at the US Open.
“She’s aggressive, she plays without limits,” he explains. “She doesn’t think – and I’ve said in a very positive way that when you’re young like that – you have all your career to think and think: ‘Oh, should I do this or that?’
“When you’re young like this and like Emma at the moment and achieve success, you just go with the flow, hit your shots without tension, without limits, with your shots. And it enables you to do things you never thought you could do.
“And he is in that very moment.”
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