Former Wimbledon champion Goran Ivanisevic believes Marion Bartoli will regret her decision to retire from tennis.
The 28-year-old Frenchwoman made the shock announcement on Wednesday night after losing to Simona Halep in the second round of the Western & Southern Open in Cincinnati.
Bartoli's decision comes only 40 days after she achieved her dream of winning Wimbledon with a straight-sets defeat of Sabine Lisicki.
Bartoli was arguably the most surprising singles champion at the All England Club since Ivanisevic in 2001, and he expects reality to bite next summer.
The Croatian was denied the chance to defend his title because of a shoulder injury but bowed out of the sport at Wimbledon in 2003.
"What she did at Wimbledon was fantastic but she will regret this decision when Wimbledon comes," said Ivanisevic, who returns to London for the Statoil Masters Tennis in December.
"There is nothing like playing at Wimbledon as Wimbledon champion."
Former French player Guy Forget worries Bartoli has made a rash decision and has urged her to take time to think it through.
Forget, who like Ivanisevic is playing in the Optima Open in Belgium this week, said: "I'm always very cautious about someone's quote right after a defeat.
"I hope she is going to change her mind. You don't want to have regrets looking back. Being a professional player is such an exceptional job and you don't want to look back in a few months or years and think, 'Why did I stop?'
"(My message would be) just don't rush it. Take time, go to the beach for a few days, go running in the park, just get your head together, spend some time with your friends.
"And, if you don't want to play the next week, just don't play it. If you want to miss the US Open, fine, but just don't quit, don't take such a radical decision only a few weeks after winning the biggest tournament in the world."
Bartoli, ranked seventh in the world, had given no indication that she was considering her future in tennis and stunned reporters at what was expected to be a routine post-match press conference.
She said: "That was actually the last match of my career. Sorry. It's time for me to retire and call it a career."
Bartoli blamed a succession of injuries for her decision - citing in particular an Achilles problem that was troubling her on the hard courts.
"My body just can't do it any more," she said. "I've already been through a lot of injuries since the beginning of the year. I've been on the tour for so long, and I really pushed through and left it all during that Wimbledon.
"I really felt I gave all the energy I have left in my body. I made my dream a reality and it will stay with me forever, but now my body just can't cope with everything.
"I have pain everywhere after 45 minutes or an hour of play. I've been doing this for so long, and body-wise I just can't do it any more."
Bartoli was inundated with messages of support on Twitter, including from Lisicki, who wrote: "You've had an unbelievable career & made your dream come true! Wishing you ALL the best girl!"