The victory propelled her to British women’s number one spot ahead of Johanna Konta and puts her on the cusp of the world's top 50 female players.
After coming through three qualifying matches to reach the main draw, Raducanu is yet to drop a set in her eight matches at Flushing Meadows.
She is the first British woman to reach a US Open semi-final since Jo Durie in 1983 and the youngest to reach a Grand Slam semi-final for 46 years.
“I have just been focusing one day at a time, taking care of each day," said Raducanu. "When you're playing tournaments, you just get into this sort of auto-pilot mode of your routines, recovering on the day off in between.
"I didn't expect to be here at all. I think my flights were booked at the end of qualifying, so it's a nice problem to have.
"I'm just really enjoying the experience. Out there on the court today, I was saying to myself, 'This could be the last time you play on Ashe, so might as well just go for it and enjoy everything'."
Who is Emma Raducanu playing in her US Open semi-final?
Raducanu will play 17th seed Maria Sakkari in Thursday's semis after the Greek beat Czech fourth seed Karolina Pliskova.
When is the match taking place?
It will be the second of the women's singles semi-finals and will start around 9pm local time in New York, which is 2am UK time in the early hours of Friday morning.
Is it on TV?
You can watch the action unfold live on Amazon Prime Video. You can sign up for £6.99 a month and watch via the Prime Video App on tablet, mobile or set top box.
Alternatively, live radio commentary is available via BBC Radio 5 Live.