Johanna Konta revealed she was still in “shock” after being forced to pull out of the Australian Open first round with a stomach strain.
The British No.1 was leading 5-4 against Slovenian Kaja Juvan before call a medical timeout after missing an overhead in the 10th game.
She told officials: “I need to get this taken care of, otherwise I can’t play.”
The world No.15 returned to court to win the set but retired afte two games in the second set.
“I pulled my ab and that made it difficult for me to serve and that is why I had to retire,” said Konta.
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“I feel like I am in a bit of shock so I don’t fully know yet anything – I haven’t yet been able to check in with the physios.
“I felt it in my second service game of the first set. I was conscious of trying to adapt and use my legs more on my serve.
“Then in my second last service game of the first set, it started to get quite painful. I tried to just manage it the best I could but in the last service game of the first set, that is where I needed to intervene with the physios to try and offload it with tape and stuff like that.
“I don’t have answers for you for why this happened. I don’t know. I haven’t had an ab issue in a very, very long time. I don’t know.”
Since reaching the quarter-finals of the 2019 US Open, Konta has only won one Grand Slam match – against Heather Watson in New York last year.
She lost in the first round in Melbourne last year and also in Paris.
Male British No.1 Dan Evans, who won his first ATP Tour title on Sunday, also lost in four sets to British No.3 Cam Norrie.