Raducanu revealed she struggled with her breathing and felt dizzy during her fourth-round Wimbledon clash with Ajla Tomljanovic on Monday before being advised to retire.
Difficulty breathing was given as the official reason for her withdrawal on Monday night but the initial lack of explanation for what caused it led to intense speculation.
John McEnroe was heavily criticised after jumping to the conclusion immediately after the match on the BBC that she could not handle the occasion, and Piers Morgan said on Twitter saying she needed to toughen up.
Andy Murray weighed in, replying to a tweet from Kevin Pietersen about mental toughness being what separated good athletes from great ones, although the former England cricketer later insisted he had not been referring to Raducanu.
Murray wrote: “No question mental toughness can be what separates the best in sport but surely both of you aren’t judging her mental toughness on yesterday’s match?!
“I think some of what he (McEnroe) said was fair yes.. however the timing of it was a bit off considering nobody had any clue what her issue was injury/illness/breathings issues etc at the time of his comments.
Several other sports stars then got behind the teenager who announced herself as a new star of British tennis by reaching the last 16 on her debut at the All England Club.
Rashford, who has taken on politicians in his bid to improve childrens’ lives for the better, drew on his own personal experience when offering his support.
It happened to me playing for the national team in U16s against Wales,” he tweeted. “I remember it to this day. No explanation for it and it never happened again. You should be very proud of yourself. The country is proud of you. Glad to read your feeling better. Onwards and upwards.”
Jude Bellingham, who became the youngest-ever player to play for England at a European Championship this summer, also got behind Raducanu, while Dina Asher-Smith revealed her pride in the teenager.