Paul Hunter admitted to playing in pain during his first-round match against Neil Robertson at The Crucible.
Hunter received a card from a well-wisher
The 27-year-old has been battling against cancer for the past year and found the going difficult against the Australian, who won 10-5.
"It's been tough for me because I've not really enjoyed playing while I've been ill," he said.
"I didn't think I would make it here because I was in a pretty bad way, but I sweated it out and battled through."
He added: "It's quite tough because I have pain in my side 24-7 now but I just have to get on with it."
Hunter's focus is now on receiving more treatment for his illness.
"I start on my third course of chemotherapy for another 16 weeks," said the Leeds star.
"I'm worse off than I was last year. This treatment is to try to stop the cancer from growing and if it works then I will have more to try to shrink it."
Meanwhile, Robertson said his victory over Hunter was not one he could celebrate.
"There was no joy in it for obvious reasons," said the 24-year-old, who will now play Stephen Lee.
"I'd been building myself up to try to block out the emotions. It's not nice to see Paul struggling and I wish him well and hope he can get through this"