Halep, who won her first major title at Roland Garros in 2018, appeared to be in control of Thursday’s match as she won the first set and broke early in the second.
But the teenager Zheng recovered to take the second set and establish an early lead in the third.
Halep, who seemed to be struggling to breathe, called on the coach twice in the final set as she lost 6-2 2-6 1-6.
Ahead of the French Open, Halep told CNN she nearly retired from tennis last year as she recovered from a calf injury and battled the continued impact of the Covid pandemic. -19.
She said her partnership with coach Patrick Mouratoglou earlier this year had “brought back that fire”, but admitted after Thursday’s defeat that the continued impact of the past two years continues to take its toll.
“I can understand why (the panic attack) happened because I had a tough two years with injuries and a lot of pressure with the pandemic and all that,” she said.
“So probably today I just broke down a bit. My brain wasn’t very strong. But now I’m fine, and that’s why I’m smiling.”
Writing on Instagram, Mouratoglou admitted after the match that he is “not doing a good enough job” coaching Halep and “expects much better from me”.
Halep replied that she was “ready for more”.
The former world number 1 has been praised for speaking openly about the panic attack, with Eurosport commentator and former player Tim Henman saying it was ‘so brave and so honest’ of her to discuss what happened. had happened.
“She’s been around for many years, she’s won big titles and it just goes to show that it can happen to anyone,” Henman said.
Zheng will play in the third round of a Grand Slam for the first time in her career when she faces Alizé Cornet on Saturday.
The world No. 74 could then face Iga Swiatek in the fourth round, the 2020 Roland-Garros champion who is on a series of 30 consecutive victories.