Emma Raducanu left fans concerned again as she called for a medical timeout during her clash at the Ningbo Open in China on Tuesday.
Raducanu was forced to retire midway through her Wuhan Open first-round clash with Ann Li last week, after appearing to struggle with illness amid 32-degree temperatures in China.
And, she appeared to suffer again in her match against Zhu Lin in the first round of the tournament in Ningbo, which lies south of Shanghai.
After winning the first set against the world No 219 6-3, Raducanu began to falter in the second and was beaten 4-6.
With the Brit losing 3-4 in that set, Raducanu called for a physio and had her blood pressure taken.
The 22-year-old was also handed something to eat and drink as she looked to recover from whatever had been troubling her, with the temperatures in the mid to late 20s still despite the clash taking place in the evening.
Emma Raducanu suffered another health scare during the Ningbo Open in China on Tuesday
Raducanu called for a physio and had her blood pressure taken during her first round match
Raducanu did return to the clash but swiftly lost the second set, before she started the third in the worst possible fashion by going 2-0 down.
At the start of that period of play, the Brit seemed to be struggling with her back and was seen stretching it out – and she called for the physio to help treat her issue.
She did pull the score back to 1-2, but badly faded amid her difficulties and was beaten 1-6 in the third set so suffer an upset.
Meanwhile, in Wuhan last week, where conditions were extremely hot and humid, Raducanu floundered from the off against her opponent Li – who she last defeated at Eastbourne this year – and lost the first set accordingly 6-1.
But Raducanu’s energy levels looked increadingly concerning heading into the second set as she struggled to make it a competitive match.
At 4-1 down, Raducanu called for a medical timeout, and had her blood pressure checked on-court.
In worrying scenes, the former US Open champion was slumped in her chair during the process, and looked to be challenged by the conditions.
‘I do feel maybe she should have called for attention earlier in the match when it was clear that she wasn’t feeling herself,’ Jonathan Overend said on commentary for Sky Sports Tennis during the timeout.
The British No 1 was forced to retire from the Wuhan Open last week amid extreme conditions
‘I suppose you’re proud out there, you don’t want to give anything away to your opponent, you don’t want to let anyone know that you’re not feeling great but the bottom line is health has to be the utmost priority.’
After her checks, Raducanu retired, shaking hands with Li and the umpire before heading off court.
Speaking ahead of her clash against Lin, Raducanu had reflected on the incident.
‘I think where it’s different is just, it’s at the end of the season, so you need to push harder physically, you’re feeling it a bit more, and mentally as well, to just focus,’ she said. ‘That’s probably the biggest difference.’
