Pam Shriver has described Sloane Stephens' slump from her US Open triumph to being horribly out of form as "the most curious six months in the history of a professional tennis player".
Stephens made an astonishing recovery from injury to win her first grand slam title on home soil at Flushing Meadows last September, thrashing fellow American Madison Keys in the final.
The 24-year-old surged over 900 ranking places in the space of a month, coming from nowhere to be crowned champion in a story which even her most optimistic supporters could surely not have scripted.
Stephens has experienced an alarming decline since her finest hour in New York, losing all seven of her matches after ruthlessly demolishing Keys.
Former world number three Shriver is baffled by her compatriot's struggles, but feels the tide will turn ahead of her first-round match against Zhang Shuai at the Australian Open on Monday.
Shriver told Omnisport: "It's the most curious six months in the history of a professional tennis player. When you think not that long ago she was just coming back from almost a year out of the game, ranked 900 in the world.
"She lost to [Simona] Halep in [Washington] DC and then she went semi-final, semi-final in two big tournaments in Canada and Cincinnati and then she turned the tables at the US Open.
"Physically and emotionally she handled the final so much better than Madison Keys, so much so that it wasn't even a contest in the end.
"But, if you look at her pattern, when she had her first grand-slam breakthrough - sensationally beating Serena Williams at the Australian Open in 2013 and losing a really tough semi to Victoria Azarenka - she then performed really poorly and started to get injured.
"You sort of think, well the US Open follows her pattern of when she does well in a major, gets distracted, struggles and for whatever reason she loses her way. Most people gain confidence when they do well in a major, but in this day and age in the women's game many have struggled after a breakthrough at a major.
"But this is an extreme, for Sloane to lose so many straight matches, it's really hard to imagine.
"Sloane obviously has such a difference between her high end, her fully confident self, and when she loses confidence, interest and struggles physically. She's too good lose that many games in a row. Obviously, it is life-changing to win a major. She had a big lie down and has not been able to get back up again, but she will be back."