Novak Djokovic pulled out of his quarter-final match against Feliciano Lopez at the Dubai Tennis Championships on Thursday, citing a problem with his right eye.
The top-ranked Serb had already lost the first set 6-3 against Lopez when he decided to call it a day, apparently struggling with an eye infection.
The withdrawal brings to an end an incredible run that saw Djokovic reach 17 successive tournament finals.
“It’s very sad when one of the greatest players ever has to retire from a match like that,” said Lopez, who moves on to face Marcos Baghdatis in the semi-finals.
Baghdatis advanced after beating Roberto Bautista-Agut 7-5, 6-0 in 97 minutes.
The second semi-finals promises to be an enthralling affair between in-form Australian Nick Kyrgios and tournament second seed Stan Wawrinka.
Kyrgios captured his maiden ATP Tour title in Marseille just a few days ago, and continues to fly high in Dubai this week.
The outspoken 20-year-old upset third seed Tomas Berdych 6-4 6-4 to advance to his second successive semi-final. He also beat Berdych in Marseille on the way to the title last week.
“I wasn’t in the greatest shape. I think I got a bit of food poisoning last night. I was really surprised with the performance I gave out there today to come out there and beat a quality player and in tough conditions. It’s probably my favourite win over the past couple of weeks,” said Kyrgios.
Wawrinka, meanwhile, needed just 75 minutes to dispatch Phillip Kohlschreiber 7-5, 6-1.