Following a second round loss at the Western and Southern Open on Wednesday, the 28-year-old Frenchwoman walked off the court and two hours later stepped into a press conference to shock everyone, saying: "I feel it's time for me to walk away."
Immediately social media exploded with fans, coaches,commentators and players, past and present, reacting with surprise and support.
"Crazy to wake up hearing about @bartoli_marion retiring but understand the feeling... Congrats on a great career," said Belgian Kim Clijsters, a former world number one who retired and then later returned to the sport to win two grand slams.
"You've had an unbelievable career & made your dream come true! Wishing you ALL the best girl," tweeted Sabine Lisicki,who was left in tears after being beaten by Bartoli in the Wimbledon final.
The Bartoli buzz dominated conversation at the Western and Southern Open with players arriving on Thursday not only to find out that the popular Frenchwoman had been knocked out of the tournament but had left the sport.
"I actually saw that on Twitter and I was like, yeah, that's some crap," world number two Victoria Azarenka told reporters."I think everybody's a little bit surprised about that.
"I think it's very brave to do that. I think she was chasing her dream for such a long time. When she got it, it felt good. So whatever makes her happy.
"There's no doubt it's been surprising for everybody."
Andy Murray, the men's Wimbledon champion, who shared the tennis spotlight with Bartoli just six weeks ago, was caught off guard but happy to see her go out a winner.
"In some ways, it's surprising but I did say in here the other day that...I think the biggest compliment you can pay an athlete is they've reached their potential, and I believe she did that," summed up world number two Murray.
"She worked exceptionally hard to get to where she's got to. She deserved to win a grand slam and maybe it was the right time for her to stop because of how hard she needed to work.
"But it was obviously surprising because you don't see it that often in sport where people kind of finish almost on the top in a way."
Described as quirky and brilliant, there was no denying that Bartoli marched to the unique beat of her own drum.
From her double-handed groundstrokes off both wings to her unorthodox training methods, Bartoli work outside the box and was celebrated for her uniqueness.
"So more power to her," said top-ranked American John Isner."She had a great career and capped it off on a very high note. I'm not talking about losing here, I'm talking about winning Wimbledon.
"Not many people can call themselves a grand slam champion,but she can."