Emma Raducanu needed a lengthy medical time-out as she came through a three-set marathon to book a blockbuster second-round meeting with defending champion Iga Swiatek at the French Open.
The 22-year-old was leading China's Wang Xinyu 6-5 in the first set when she called for the doctor, rubbing ice on her cheeks and round her eyes as she had her blood pressure checked.
There were fears that Raducanu, who has had a history of injury and illness issues throughout her career, would have to retire from the match.
But after three minutes of treatment she came back on to the court and confidently served out the set to love.
Wang rallied to take the second set but, in front of a big crowd on a cramped Court Eight, Raducanu hit back to complete a gutsy 7-5 4-6 6-3 victory in two hours and 44 minutes - the joint-longest match of her career on clay.
Prior to the match, Raducanu had admitted the back problem she suffered in Strasbourg last week was was still not 100 per cent right.
The 2021 US champion has had to overcome a phobia of needles to undergo acupuncture in a bid to ease the issue.
Raducanu's movement did not appear to be hindered by the problem, but her energy levels did seem low.
At the start of the second, the British number two flagged again allowing Wang, who is ranked two places beneath her at 43 in the world, to move 5-1 ahead.
Raducanu dug deep to claw both breaks back, but 23-year-old Wang - a former doubles champion at Roland Garros - brought up set points on her opponent's serve and took the second to level the match.
Raducanu disappeared off court briefly at the changeover and upon her return promptly grabbed a decisive break.
She squandered two match points on her own serve but a Wang double-fault in the next game sealed a gruelling win.
"I was really just flat and struggling at the start but I'm happy to have got through," she said.
"I can take positives in the fact a lot of top players, in the first round, have struggled but got through and given themselves another opportunity. My heart and fight came through today and I'm very proud of that."
Four-time champion Swiatek had earlier stretched her winning streak at the French Open to 22 matches, the Polish world number five beating Slovakia's Rebecca Sramkova 6-3 6-3.