World number one Garbine Muguruza retired feeling unwell at the China Open as US Open winner Sloane Stephens was again defeated in the first round.
Spaniard Muguruza, 23, lost the first set 6-1 to unseeded Barbora Strycova, 31, from the Czech Republic.
Wimbledon champion Muguruza then called a medical timeout at 2-0 down in the second set and retired after having her pulse taken courtside in Beijing.
“It’s very tough, I got a virus in Wuhan,” said the 2015 Beijing champion.
“I couldn’t perform today. It’s the easy way to think ‘don’t go on the court’. I want to feel like giving the last chance, going on the court, just hit a few balls, see how I’m going to feel, try to turn things around.
“I don’t want to retire before the tournament starts.”
Fifteenth seed Stephens lost 6-3 6-0 to qualifier and fellow American Christina McHale in just 62 minutes.
The defeat by the world number 79 extends Stephens’ poor run since clinching her first Grand Slam last month.
Last week she also fell at the first hurdle, to China’s world number 52 Wang Qiang in the Wuhan Open.
“Tough day, not really much to say,” said the world number 17.
“Obviously not a great match so just forget about it and move on, try to have a better level for the next tournament (Hong Kong).”
