Maria Sharapova opened up on the despair she feels in defeat after she was ruthlessly knocked out of the China Open in the third round by Romania's Simona Halep on Wednesday.
The world number two was an emphatic 6-2, 6-2 winner to leave five-time Grand Slam champion Sharapova still searching for her first title since returning from a doping ban in April.
It was the 26-year-old Halep's first victory over the Russian in eight meetings and she will play another Russian, Daria Kasatkina, in the quarter-finals.
The unseeded Kasatkina, 20, stunned defending champion Agnieszka Radwanska in the final match of the day, 4-6, 7-5, 6-2. 
After her defeat Sharapova, a former number one now ranked 104 following her 15-month suspension for taking meldonium, gave an insight into the rollercoaster of emotions in top-level tennis.
"Hard work is not good enough any more, maybe it was -- I don't know how many years ago -- but that's just not a factor any more," said the 30-year-old, asked about comments in a book she recently released.
"The reason I say that is there's some incredible moments, very high moments, and there are very low moments. 
"There have been times where I get off the court and you think, I don't wish this on my future child. 
"The feeling is so tough and disappointing."  
Halep, the second seed on Beijing's outdoor hard courts, is now the favourite with world number one Garbine Muguruza exiting in the first round with a virus.
Sharapova said it was the best Halep had played against her -- and Halep agreed.
The two met in the first round at the US Open a few weeks ago and Halep said she was delighted to finally taste victory against Sharapova: "I'm really happy that I could do this. 
"It's my first victory against her and I just want to enjoy the moment."  
- Redemption for Kyrgios? -
Nick Kyrgios said he wanted to make up for his notorious meltdown in Shanghai last year as he beat Mischa Zverev in the second round in Beijing.
A year ago the supremely talented but combustible Kyrgios was suspended for his petulant behaviour at the Shanghai Masters, where he argued with the crowd and appeared to give away points in caving in to the German journeyman.
The enigmatic Australian, seeded eighth in the Chinese capital, smashed his racquet on the floor in anger, bending the head in half, when he conceded the opening set on Wednesday.
That earned the world number 19 a warning from the umpire and raised the spectre of one year ago.
But the 22-year-old returned for the second set with renewed determination and coasted into the quarter-finals 3-6, 6-2, 6-2. 
Kyrgios said facing Zverev -- older brother of rising star Alexander -- a year after Shanghai, and again in China, was the perfect opportunity to show how far he has come.
"I just wanted to go out there today and kind of redeem myself a little bit from last year," he said, adding: "I just wanted to prove to myself how much I have improved."
During one changeover the Australian appeared so relaxed that he sat back on his chair, arms behind his head, and sang along with a pop hit being played over the stadium loudspeakers.
"Nothing really, just chilling out," Kyrgios said afterwards, asked about his behaviour.
He plays the Belgian qualifier Steve Darcis in the last eight, where they were joined by third seed Grigor Dimitrov, who battled past the Argentine Juan Martin del Potro 7-6 (8/6), 7-5.
Bulgaria's Dimitrov takes on fifth seed Roberto Bautista Agut of Spain.