“It is a remarkable achievement at such a young age, and is 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.”
The Queen also sent a letter to Raducanu, which she said she would be framing.
“It meant everything to get a message from Her Majesty,” the tennis star told the BBC.
“She’s such a great inspiration and role model for the whole country so to have a note from her…
“I was extremely honoured and very very grateful that she took notice of my tennis. I can’t believe it. I’m maybe going to frame that letter or something.”