Rafael Nadal’s hopes of completing a rare calendar-year grand slam ended on Thursday when the Spaniard pulled out of his highly-anticipated Wimbledon semi-final showdown with Australian Nick Kyrgios with an abdominal strain.

“I have to pull out of the tournament as I have been suffering with abdominal pain,” said the 36-year-old, the holder of a men’s record 22 Grand Slam titles.

“I can’t imagine winning two matches with this (pain). For me the most important thing is happiness rather than the title even though everyone knows how much effort I put into this as I can't risk being out of the sport for two to three months. I am very sad.”

Nadal had triumphed at the Australian and French Opens this year and had been hoping to become the first man since Rod Laver in 1969 to complete the calendar-year slam.

Nadal’s withdrawal mean Kyrgios becomes the first Australian to reach the men’s final at the All England Club since Mark Philippoussis In 2003.

Nadal, who entered the tournament with concerns about his chronically injured foot, tore a muscle in his abdomen during play earlier in the tournament.

He aggravated it in his five-set win over Taylor Fritz in the quarter finals on Wednesday.

During that match, Nadal took a medical timeout in the second set. From the stands, his father and other members of his family motioned for him to stop playing rather than risk further injury, but Nadal ignored their pleas and pulled off one of the more remarkable comeback wins of a career that has seen many of them.

After the match, Nadal said he was worried that he might not be able to play in the semi-final and that he planned to have a scan to determine the extent of the injury.

“The decision at the end — all the decisions — are the player’s decision, but at the same time I need to know different opinions and I need to check everything the proper way, no? That is even something more important than win Wimbledon, that is the health,” he had said.

Nadal’s game had been improving with each match, something he also noted after his win over Fritz, despite this being his first tournament on grass in three years.

“The level of tennis, if we put away the problems, something that’s difficult, the level of tennis, the feeling that I am having with the ball on my hand is honestly great. I am feeling myself playing very well,” he said.

With Nadal’s withdrawal, Kyrgios receives a walkover in what would have been his first grand slam singles semi-final. Kyrgios, 27, had never made a grand slam singles semi-final previously during a career filled with controversy.

The win against Fritz had put Nadal just nine wins away from a calendar-year grand slam.

On Thursday, he turned up for practice at Wimbledon. He was hitting forehands and backhands on the practice courts at Aorangi Park and also went through his service motions.

Nadal's serve speed dropped drastically from the end of the second set against Fritz, after he took a medical time-out, but he still clinched the tie in a final-set tiebreaker.