The Queen last night led tributes to Emma Raducanu’s “remarkable achievement” while Kate Middleton and Prince William praised her “incredible victory”.

The Monarch’s warm letter of congratulations to the 18-year-old superstar was personally delivered by her representative in New York minutes after her stunning triumph in the US Open.

Raducanu beat Canadian Leylah Fernandez 6-4, 6-3 at the Arthur Ashe stadium to become the first qualifier ever to win a major tournament.

She didn’t drop a single set on the way to glory in one of the greatest sporting achievements of all time.

In her congratulatory message, the Queen led an outpouring of congratulations along with the Duke and Duchess of Cambridge.

The Monarch said: “It is a remarkable achievement at such a young age, and is a testament to your hard work and dedication.

“I have no doubt your outstanding performance, and that of your opponent Leylah Fernandez, will inspire the next generation of tennis players.

“I send my warmest good wishes to you and your many supporters,” She said.

A tweet from the official account of the Duke and Duchess of Cambridge congratulated the teenager and her opponent on their “amazing achievements” at the tournament.

It read: “Huge congratulations @EmmaRaducanu on your stunning performances and historic Grand Slam victory! Incredible – we are all so proud of you.