The Brit is the first qualifier to reach the last four in New York and she did it on the back of 23 winners to just 12 unforced errors along with six aces. She also broke Bencic three times and got 70 percent of the Swiss' first serve returns in play.
Next up for Raducanu is 17th seed Maria Sakkari with a place in Saturday's championship match on the line. The 18-year old will look to create more history as she attempts to become the first qualifier to reach a Grand Slam final.
British teenager into semifinals after another stunning victory
Early nerves got to Raducanu as she was broken in the opening game of the match and Bencic followed with a pair of comfortable holds to extend her lead to 3-1.
The Brit came roaring back, holding to love and breaking on her second chance after the Swiss netted a backhand. A third straight game followed with a hold, giving Raducanu her first lead of the match.
Back-to-back forehand winners from the teenager earned her a second consecutive break and a 5-3 lead. She raced to double set point and a strong serve forced a forehand error from Bencic and gave her the edge.
Raducanu saved three break points in the second game of the second set to level at 1-1 and in the fifth game, she was handed a break when the 11th seed double-faulted to go in front 3-2.
Bencic avoided falling behind further when she saved break point in the seventh game of the set, but she never got another look at a break and on match point, Raducanu hammered a backhand that the Swiss had no answer for.