Karolina Pliskova on Wednesday became the fifth player from the world’s top 20 to withdraw from an injury-ravaged Qatar Open.
Top seed Simona Halep eased into the quarter-finals with a 6-2, 6-3 win over Lesia Tsurenko, but fifth-ranked Pliskova joined Caroline Wozniacki, Ashleigh Barty and Caroline Garcia as players who have pulled out since the tournament began.
Newly-crowned Australian Open champion and world number one Naomi Osaka also withdrew days before the start.
“From the first day I was not feeling great and not ready,” the Czech star and former world number one told reporters.
“I have never felt actually this way. It’s normal that you are tired, of course, when you are travelling and playing a lot of matches.
“But I just feel somehow my body is not ready, I had a temperature for a few days.
“I don’t have any neck pain or something, but I just feel overall like super tired, and my muscles are just hurting from the morning without even doing anything.
“So I’m just not able to compete 100 per cent today.”
Pliskova, the number two seed in Qatar and 2017 champion, was due to play her first match of the tournament on Wednesday, against Belgium’s Elise Mertens.
Unusually, her place in the tournament was taken by her twin sister, Kristyna, who lost to the Belgian in straight sets, 6-2, 7-6 (7/3).
Karolina played in a gruelling three-hour Fed Cup tie against Romania’s Halep at the weekend and said “it would be better” if such matches were played on Friday and Saturday rather than over the weekend.
Asked if she thought players should think more about fans and tournament organisers before withdrawing, Pliskova said: “I don’t know what else you want to do.
“If the players are sick, what can they do?
She added: “If it’s not possible, it’s not possible.”
Despite the withdrawals there is still a strong field left standing in Doha.
Halep cruised through in her first appearance of the tournament, winning five straight games in the second set to secure victory over Ukraine’s Tsurenko.
“It’s been a good match,” said Halep, before adding: “I’m happy that I could win in that way.”
The Romanian also called for more time for players to recuperate after the Fed Cup.
“It’s really exhausting to come straight from Fed Cup for playing a tournament,” she said.
“It’s not easy, it’s better if we have a week off between.”
Three-time Grand Slam winner, Germany’s Angelique Kerber beat Anett Kontaveit 6-1, 7-6 (7/3), despite late resistance from the Estonian.
Also through is Kiki Bertens of the Netherlands.
The number five seed, who also admitted to not feeling well, beat Spain’s Carla Suarez Navarro, the 2016 Qatar champion, 2-6, 6-1, 6-1.
And Elina Svitolina of Ukraine beat Latvia’s Jelena Ostapenko 6-4, 6-4.