Former champion Simona Halep revealed she suffered a panic attack in her French Open defeat to China's Zheng Qinwen on Thursday.

The distressed 19th-seeded Romanian slumped in her chair at the end of the first set and required the attention of the doctor.

"It was just a panic attack. I didn't know how to handle it, because I don't have it often," said the 2018 French Open and 2019 Wimbledon winner.

"I was leading the match. I was playing well. I lost it. I couldn't focus.

"After the match, it was pretty tough. But now I'm good. I'm recovered, and I will learn from this episode. Nothing dangerous. The doctors checked everything. Everything was perfect."

Zheng, just 19 and making her Paris debut, triumphed 2-6, 6-2, 6-1 and will face either 2017 champion Jelena Ostapenko or France's Alize Cornet for a place in the last 16. (AFP)