Baltacha had beaten Nicha Lertpitaksinchai on Tuesday
British number one Elena Baltacha has been knocked out of the Pattaya Open in Thailand following a 2-6 6-1 6-4 defeat at the hands of sixth seed Shuai Peng.
The 27-year-old had reached the last 16 after beating Nicha Lertpitaksinchai in straight sets and began her second contest well, taking the first set 6-2.
But thereafter her Chinese opponent took control and secured victory in a little under two hours.
Peng now plays number one seed Vera Zvonareva in the next round.
It was a disappointing result for Baltacha on Wednesday, coming three days after after she helped Great Britain's women finish fifth in the Fed Cup Europe/Africa Zone Group One after a 2-0 play-off win over Croatia in Israel.
The British number one, who has been struggling with a knee problem in recent weeks, had begun in dominant fashion against Peng before slowly losing control in Thailand and losing in one hour 51 minutes.
She wrote on
her Twitter page:
"Lost 6-4 in the 3rd! tough match..gave it everything, but just fell short!!.its onwards and upwards!"
It ensured Peng's progression to at least the quarter-finals in Pattaya for a third time in five years and will next face the winner between top-seeded Vera Zvonareva and local player Nungnadda Wannasuk.
When you are down match point at 4-5, 0-40, you need luck as well
Ana Ivanovic had to dig deep to secure her spot in the quarter-finals as the second seed came from a set down to see off Jill Craybas 4-6 6-1 7-5.
"It was tough, especially mentally, in the end," the former world number one said. "I was happy to pull off that victory. Winning match like that was good for me."
The Serb will face fifth-seeded Italian Roberta Vinci, who beat China's Zhang Shuai 7-5 6-1.
Third seed Maria Kirilenko crashed out, however, over three thrilling sets to to Kazakhstan qualifier Galina Voskoboeva.
The Russian, who as the second seed in 2007 was knocked out in the first round, led 6-1, 5-2 and was serving with three match points at 5-4, before crumbling with nerves.
Voskoboeva, who finally came through 1-6 7-5 6-4, said: "I wasn't in the match at all until I was down 3-0 in the second set.
"But I started to play better from then. When you are down match point at 4-5, 0-40, you need luck as well. But I didn't think about that. I just played point by point."