Emma Raducanu suffered more physical difficulties in a second-round Australian Open exit to China's Wang Yafan.
The former US Open champion, playing only her fourth match since returning from eight months out and three surgeries, had battled back strongly from a set and a break down to force a deciding set.
But Raducanu then appeared to struggle with breathing difficulties, clutching at her chest and abdomen before calling the trainer after two games.
She had her blood pressure checked and took some pills before resuming, and she battled hard to try to turn the match around but Wang held firm to win 6-4 4-6 6-4 after two hours and 55 minutes.
Raducanu comfortably won her first-round match against Shelby Rogers, but the American looked very rusty after a long break herself which made it difficult to gauge the 21-year-old’s true level.
This was a much bigger test, with Wang a former top-50 player now ranked 94 who is still working her way back up the game after choosing not to travel amid China’s restrictive Covid policies.
The 29-year-old’s game initially held up better than Raducanu’s in the breezy conditions and she opened a 5-2 lead in the first set.
The match was again being played on the relatively small 1573 Arena, and queues stretched from each entrance with fans eager to watch the contest.
Raducanu had the majority of the support, and she sparked hopes of a comeback by winning consecutive games to make it 5-4, but Wang served it out at the second time of asking.
There were too many errors off the racket of the British player, and she dropped serve again at the start of the second set.
But Raducanu dug in and gradually began to find her range, finally taking her fifth break point in a long fourth game to draw level.
The 21-year-old is determined to stick to an aggressive game plan following her comeback and her forehand was now looking the dominant shot.
She broke to lead 5-3 with a sizzling cross-court winner but tentativeness crept in as she tried to serve out the set, with two chances going begging.
Raducanu did not let the disappointment affect her, though, and refused to be hesitant when more chances arrived on Wang’s serve, drilling a backhand winner to clinch a mammoth 65-minute set.
Both players took a bathroom break but that did not alleviate the discomfort Raducanu was feeling, and there was doubt over whether she would be able to continue.
She improved physically again as the match went on and will feel she could have turned the set around but a final backhand into the net signalled her demise.
Raducanu revealed in her press conference that she was feeling sick having gone into the contest under the weather.
"I think I just had a bit of a stomach bug beforehand," she said. "Now I feel a little bit better. I had some time.
"During the match, third set I was 30-0 up serving. Then all of a sudden I just felt so sick, just really weak and nauseous. Throughout the third set I think everyone could see it was a bit of a battle.
"Like physically, body-wise, I felt fine. It was more I was throwing up in my mouth. Then after the match, it came out. Now I'm OK. I’ll get over it. It just sucks with the timing.
"I was actually feeling good about my tennis. Mentally, I don’t know why, I just felt really composed the entire time. Even in the first set when I was making a ton of errors with the wind, I kind of always had this feeling that I was coming back, just tidy up the errors. I felt pretty composed throughout."
Raducanu is no stranger to medical time-outs and retirements but she was determined to keep going this time.
"I’ve been in that situation before in matches, whether it was with illness or injury, and retired a few times," she said.
"With what I went through last year, you feel awful right now, at some points I couldn’t really see the ball very well, but I think it’s made me so much tougher. There was no way I was going to pull out. She was going to have to beat me, and she did. She served it out."
Iga Swiatek (above) survived a major scare to defeat Danielle Collins and reach the third round, with the American announcing she would be retiring at the end of the season.
The world number one lost to Collins in the semi-finals in Melbourne two years ago and it appeared history was about to repeat itself when the American took a 4-1 lead in the deciding set under the roof on Rod Laver Arena.
But Swiatek responded with five games in a row to claim a 6-4 3-6 6-4 victory and set up a clash with Czech teenager Linda Noskova.
The 30-year-old American, who had a 4-1 lead in the deciding set, said she was sick of the travel and wanted to have a family.
"This is going to be my last season, actually, competing," Collins told reporters after racing off Rod Laver Arena and straight into her press conference.
"I don't really know exactly when, but this will be my last season and I'm really looking forward to that.
"I have other things that I'd like to accomplish in my life outside of tennis, and would like to be able to have the time to be able to do that. Obviously having kids is a big priority for me."
Her peak ranking of seventh in the world came in 2022 after she had beaten Swiatek in the semi-finals at Melbourne Park before going on to lose to Ash Barty in the final.
Swiatek was emotionally drained at the end of the contest,
"I was at the airport already," she said.
"I wanted to fight until the end. She played perfectly so I knew it would be hard for anybody to maintain that level. I waited for the mistakes to come. I'm really proud of myself because it wasn't easy."
The semi-final loss was the only one of five previous meetings with Collins that Swiatek had not won, and she lost only one game the last time they faced each other in Cincinnati last summer.
The top seed edged a tight first set disrupted by a brief rain break but the aggression of Collins was troubling the top seed and the American, who also made the semi-finals here in 2019, won five games in a row to take a 5-1 lead in the second set.
She showed nerves, hitting four double faults as she failed to serve it out at the first time of asking, but she was rock solid on her second opportunity.
Swiatek found returns drilled back at her feet and she was staring at the exit door when Collins broke serve twice in succession to lead 4-1 in the deciding set.
However, the American tightened up with the finish line in sight and Swiatek came roaring back, clinching victory on her third match point with a backhand into the corner.
Swiatek applied strapping under her left knee at the start of the third set, but she played down concerns, saying: "I've been struggling a little bit with my knee since (the WTA Finals in) Cancun. I have ups and downs but it's not like it affects my game. You don't have to be worried."
Elena Rybakina was beaten by Anna Blinkova in a record-breaking encounter.
Rybakina, the third seed and last year's beaten finalist, also appeared like she might escape after saving two match points to force a tie-break against 57th-ranked Blinkova.
But, more than half an hour later, Blinkova finally clinched a 6-4 4-6 7-6 (22-20) victory on her 10th match point, with Rybakina having seen six opportunities go begging.
It was the longest tie-break in a singles match in grand slam history.
For Blinkova, it is also the biggest win of her career, and she said: "I don’t know what to say. It was super tough. I just tried to stay focused on every point.
"I had so many match points. I tried to be aggressive at these moments but my hand was shaking and my legs too. I tried to be calm as hard as I could and I’m super happy to win in the end.
"This day I will remember for the rest of my life. Especially on this court, with this crowd. I will never forget it. It’s the best day of my life so far."
On a day of high drama at Melbourne Park, fifth seed Jessica Pegula was also ousted, going down 6-4 6-2 to France's Clara Burel, while former finalist Sloane Stephens beat 14th seed Daria Kasatkina 4-6 6-3 6-3.
