Rafael Nadal will have a scan on an abdominal injury before his Wimbledon semi-final after it almost forced him to retire from his last-eight match.

The Spaniard, who faces Nick Kyrgios on Friday, said he ignored calls from his dad and sister to quit as he struggled with his movement against Taylor Fritz.

Nadal had a medical timeout and somehow - even he said he did not know-how - came from behind to win in five sets.

"[Retiring] is something that I hate to do," the 36-year-old said.

"So I just keep trying, and that's it."

He also had to strap on his abdomen during his previous match but said the pain had got worse during Wednesday's 3-6 7-5 3-6 7-5 7-6 (10-4) victory over American Fritz.

"It's obvious that today is nothing new. I had these feelings for a couple of days. Without a doubt, today was the worst day," he said.

"[There has] been an important increase of pain and limitation. Tomorrow I am going to have some more tests."

Nadal says he is well used to pain, and playing with problems, during a career in which he has won a men's record 22 Grand Slam singles titles.

Only last month, he won his 14th French Open title without being able to feel his left foot as it was anesthetised because of a chronic condition.

But he will not jeopardise his health when deciding whether he can play Kyrgios on Friday to continue his bid for a calendar Grand Slam, having already won the Australian and French Open titles this year.

"[There is] something more important than winning Wimbledon, that is health," he said.

He went off the court during the second set against Fritz, with the doctor giving him anti-inflammatories and painkillers and the physio trying to relax the muscles.

"It's difficult," he said. "Nothing can be fixed when you have a thing like this. That's it.

"I just wanted to give myself a chance. [It is] not easy to leave the tournament. Not easy to leave Wimbledon, even if the pain was hard."

Asked what he thought his chances were of playing on Friday, Nadal replied: "I don't know. Honestly, I can't give you a clear answer because if I gave you a clear answer and tomorrow another thing happens, I will be a liar."