Raducanu thwarted the chances of becoming the first qualifier to win a grand slam during the Open era on Saturday, beating teenager Leylah Fernandez in the final at Flushing Meadows.
Her breathtaking performance in New York came after a promising debut at Wimbledon just two months before, where she reached the fourth round before retiring with “breathing difficulties”.
“Completely unexpected. Never thought it would happen in my life to see an 18- and 19-year-old do it,” McEnroe told CNN’s Christiane Amanpour, who spoke about the all-teen final at the US Open.
“I think the women’s match is more open than it has ever been, so it’s a sign that many more players think they have a chance.
“I can not imagine anyone in her [Raducanu] the camp expected this. Winning the US Open without losing a set, it’s crazy. She is an amazing athlete, she seems like an amazing child. “
After Raducanus’ withdrawal from Wimbledon, McEnroe was criticized for saying the situation had become “too much” for her.
At the time, it was not clear what made the youngster stop playing, but she later said that “the whole experience caught up with me” and that she began to “breathe heavily and feel dizzy” after a series of “super intense rallies”.
McEnroe received backlash from people who said he questioned the youngster’s mental strength, but insisted he never intended to cause offense and only ever intended to support that breakthrough star.
“I meant exactly what I said,” he added. “I tried little to relate it to my experience when I first went to Wimbledon also as an 18-year-old and managed to qualify as Emma did.
“I played Jimmy Connors, I had not been to Center Court. I remember my leg shaking and being totally overwhelmed by the experience and almost glad I did not win.
“There are a lot of big disadvantages, but there is also pressure that you put on yourself and expectations that others put on you.
“Compared to many other things I have said before, I think it was for me as vanilla as it comes. I supported her a lot, I thought at the time.”
The seven-time winner of grand slam singles — who was known for his midfield games — says he hopes Raducanu can handle the newfound attention to her career.
The teenager was barely known outside of tennis before this year, but is now one of the biggest stars in the game.
“I do not think you could do it better than she did [at the U.S. Open]”Added McEnroe.” It’s crazy that she’s been able to do this. “
“Of course there is pressure with it, expectation comes with it. I’m sure she expects to win a lot more going forward.”