Chengdu - Marcos Baghdatis retired in agony from the final of the Chengdu Open on Sunday after suffering severe back spasms, handing the title to Uzbekistan's Denis Istomin.
Istomin was leading 3-2 in the first set when the Cypriot collapsed on the court and was unable to continue.
Baghdatis had to be helped carefully back to his seat, where he buried his head in his towel.
"I was feeling a bit of pain in my back during the week, but late after my match last night I felt some spasms," said the 32-year-old.
"This morning I woke up a bit the same. After my warm-up, it got worse."
Baghdatis said the spasms held off for the first few games of the final at Chengdu in southwest China after intensive physiotherapy, before striking again.
"I've had back issues before, but not like this," he said.
Despite the retirement Baghdatis is set to return to the top 100 in the world.
Istomin, for whom this was a second ATP crown, is projected to rise to 53 in the rankings from 78.
"Of course I want to win the title, but not this way. I hope he gets better and will be okay for the rest of the season," said Istomin, 31.