Elina Svitolina hopes the agonising back spasms that forced her to withdraw early in her Australian Open fourth-round clash with Czech giant-killer Linda Noskova will only be a short-term problem.
After receiving medical treatment on Monday when trailing 0-2, the No.19 seed only lasted one more game before pulling out.
She left Margaret Court Arena in a flood of tears.
Svitolina took a year-long break from the tour for the birth of her daughter Skai in 2022 and had reached at least the round of 16 in three of the four majors since her return.
"I've had some injuries to my back before where it just was tiredness the next day of the match, but this one was really out of nowhere," Svitolina said.
"I felt like someone shot me in the back.
"But hopefully I will be back training in maybe one week.
"Of course, the long flight I had to Australia, that's not going to help.
"I will have to take one day at a time, have to do my recovery, do the scan as soon as I get back home, and go from there.
"Hopefully I don't have something serious."
Noskova, who beat Poland's world No.1 Iga Swiatek in a huge third-round upset, said she felt for Svitolina.
"Obviously today was not the way I had planned to win," Noskova said.
"I feel sorry for Elina, I hope she gets very well soon."
Noskova's quarter-final opponent will another unseeded player, Ukrainian qualifier Dayana Yastremska, who downed former world No.1 Victoria Azarenka from Belarus 7-6 (8-6) 6-4.
"It feels like my heart is going to jump out of my body," said an emotional Yastremska, who won six of the last seven games and hit 37 winners in the see-sawing encounter.
"I was losing the tiebreak, I was losing the second set, I always felt like I was running behind the train.
"But I think I'm a little bit of a fighter, so that's why I won this match."
Having previously seen off the challenge of reigning Wimbledon champ Marketa Vondrousova in the opening round, Yastremska became the first qualifier since Jelena Dokic in 1999 to beat two major winners at the Open.
As has regularly been the case at the 2024 Open when a Ukrainian has faced an opponent from Russia or Belarus, Yastremska refused to shake Azarenka's hand at the conclusion of the match.
Despite the ongoing Russian invasion of Ukraine, players from Russia and ally Belarus are allowed to compete on tour, but not officially under their countries' banners.
The 34-year-old Azarenka won the 2012 and 2013 Australian Open crowns.
Chinese 12th seed Qinwen Zheng wasted no time qualifying for her second grand slam quarter-final, smashing France's Oceane Dodin 6-0 6-3 in less than an hour on Monday night.
Zheng, who has the strong support of 2014 Australian Open champion Li Na, will battle Russian Anna Kalinskaya in a last-eight match.
World No.75 Kalinskaya, who had never made it past the second round of a major before this tournament, breezed past Italian Jasmine Paolini 6-4 6-2.
The 25-year-old had lost all four previous matches at Melbourne Park before this year's event.
