Top seed Sabine Lisicki has withdrawn from the Pattaya Open tennis tournament due to a right shoulder injury.
The 2013 runner-up struggled in her first-round match on Monday, taking two hours to overcome Croatia's Donna Vekic 7-5 2-6 6-4.
She admitted after the match that it had been almost impossible for her to serve effectively.
"It was pretty obvious I wasn't able to serve in the second and third sets," she said on Tuesday.
"I love the tournament so much, especially after last year playing in the finals. I wanted to do better this year. I tried everything and won the match yesterday and was hoping it could get better overnight, but unfortunately it didn't.
"Now the first plan is for me to get healthy again. I will see my doctors at home and make plans from there."
Lisicki's second-round opponent, Czech Andrea Hlavackova, advances to the quarter-finals.
Earlier, second-seeded Russian Svetlana Kuznetsova eased through by defeating China's Zhang Shuai 6-0 7-6 (7-3) and Chinese eighth seed Peng Shuai beat Austrian Patricia Mayr-Achleitner 6-1 7-6 (7-1).
But seventh seed Bethanie Mattek-Sands of the United States was upset 6-2 6-4 by Czech Karolina Pliskova.
Spain's Anabel Medina Garrigues suffered the first 6-0 6-0 defeat of her 16-year career as she lost to American Alison Riske in just 58 minutes.
