Li Na, who became the first Chinese player to reach a Grand Slam singles final last month in Melbourne, followed it by missing four successive match points to lose her opening match in the Dubai Open on Wednesday.
The fifth-seeded Chinese player was 6-2 up in the second set tie-break against Yanina Wickmayer, the world number 25 from Belgium, but, after failing to convert any of them, slid frustratingly to a 6-7 (6/8), 7-6 (10/8), 6-2 defeat.
There had been signs of ring rustiness from Li in the first set when she was unable to convert her first two set points, and again in the second set, when she failed to convert three break points in a row.
But having got to within one good blow of victory in the second set, it seemed certain that her more complete all-court game and better ground-stroking angles would get her over the line.
Instead, Wickmayer played by far her most consistently forcing tennis on the four match points, and after taking the contest into the decider saw Li's standard fall away sharply. The last four games tumbled quickly in the direction of the unseeded player.
Asked if it were the best win of her career, Wickmayer said:"Probably, yes. She's a top ten player, and she's a great player, and she played really well at the beginning of the year, so I am very, very happy."
Wickmayer is coached by her father Marc, but has just given a three-month trial to Vladimir Platenik, about whom she said: "I hope he's really happy."
Wickmayer next plays Shahar Peer, the first Israeli woman ever to compete in the United Arab Emirates, who reached the last 16 with a 6-4, 6-2 win over Alexandra Dulgheru, a top 30 player from Romania.
The winner of that could become the last obstacle for Caroline Wozniacki to hurdle on Friday if she is to regain the world number one spot from Kim Clijsters.
Wozniacki moved to within two wins of doing that - but only after her opponent, Anna Chakvetadze, suddenly and dramatically fainted.
One moment the former world number five from Russia was standing behind the baseline, preparing to serve, and the next she was sinking like a blasted chimney and lying unconscious on the court.
A doctor, a trainer, the umpire and Wozniacki all rushed to help Chakvetadze, and after a seven minute delay in which her blood pressure was checked, she played one more point before retiring with the score at 6-1, 3-5 and 40-15.
"It was a shock," said Wozniacki. "It was scary. She is a good friend of mine, but to see anyone collapse on the other side of the net is not a good sight. It was quite a surprise."
It was less of a surprise for those who had seen how sluggish Chakvetadze had been while somehow getting past Daniela Hantuchova the previous day, or those who noticed how poorly she looked between points.
It was remarkable that she even tried to play one more rally after her fall. It had taken five minutes before she was able to get up, and after being helped to the bench, she still looked too weak to do much.
One fault and one tepid serve was all it took for her to be convinced of this, and after a hug from Wozniacki she was taken away for further treatment.
It made it all the more creditable how Chakvetadze had progressed to within sight of winning the scond set after losing the first limply in only 23 minutes. It was such a turn-around it even made Wozniacki throw her racket in frustration, a rarity for her.
"The first set was so short I didn't get into the match too much," Wozniacki explained. "She was making so many mistakes and I didn't get any rhythm.
"Then suddenly she started to go for it and I needed time to get back. I had only just started to play better towards the end."
Wozniacki now plays Ayumi Morita, a Japanese qualifier who disappointed the organisers by removing arguably the tournament's greatest draw, Sania Mirza, the Indian star now based in Dubai.