Raducanu – who is making her debut at the US Open this year – became the first qualifier to reach the semi-finals in the Open Era.

The 18-year-old LTA Pro-Scholarship Programme player also became only the third woman outside the top-100 to reach the final four at Flushing Meadows – joining Billie Jean King and Kim Clijsters.

Raducanu will become the new British No.1 when the rankings are updated on Monday.

The match started in a similar vein to Raducanu’s fourth round clash with Shelby Rogers. Bencic’s experience showed in the early exchanges and three unforced errors from the young Brit in her first service game, gave her opponent the early break.

As the set progressed, Raducanu quickly adjusted to the power and pace behind Bencic’s groundstrokes and gradually the momentum started to shift in her favour.

On a pivotal rally at 2-3, 30-30, Bencic made a mistake to set up the Brit’s first break point and at the second time of asking, she seized the opportunity.

Towards the end of the first set, the winners started flying off Raducanu’s racket – she hit 13 in the opening set alone, finding great results off her forehand down the line.

She sealed the vital break for 5-3 and then displayed composure beyond her years to serve out the set with ease – advantage Raducanu.

At the start of the second set, she missed a costly approach shot on the Bencic serve at 15-30, which would have set up break point – giving the Olympic gold medallist a lifeline.

It was then Raducanu’s turn to play on the defensive as she was forced to save three break points in the second game with some pinpoint serving.

Bencic’s serve has been a weapon all year, with the Swiss star ranking 19th in service points won this year (60%) but Raducanu’s return game has been on a different level this week. She dispatched a couple of second serves for winners and Bencic’s fourth double fault gifted the Brit the all-important break.

Bencic had to do everything she could just to stay within striking distance on the Brit, but serving for the set, Raducanu showed a champion’s mentality. She lost the first two points but fought back to clinch the biggest win of her career.

In the semi-final she will face either fourth seed Karolina Pliskova or the in-form Maria Sakkari.