Novak Djokovic was forced to retire in the quarter-finals of the Dubai Duty Free Championships after the world No1 lost the first set to Feliciano López.
Djokovic called for the ATP trainer while trailing 1-2. He kept pointing to his face as he spoke to the trainer, but eventually got up to play.
However, he quit the match after the Spaniard closed out the set 6-3.
Lopez said Djokovic told him that he had an eye infection "since a few days already."
Djokovic's retirement means this will be the first tournament in more than a year where he hasn't reached the final.
Lopez will play unseeded Marcos Baghdatis of Cyprus in the semifinals. Baghdatis upset fourth-seeded Roberto Bautista Agut of Spain 7-5, 6-0 in the quarterfinals.
Friday’s semi-final will be the first contest between the pair since their infamous match in Montreal last August, when on-court microphones recorded the Australian Kyrgios walking to the net and saying: “Kokkinakis banged your girlfriend. Sorry to tell you that mate” – an apparent reference to Kyrgios’s Davis Cup team-mate Thanasi Kokkinakis.
Kyrgios subsequently apologised for the comments, which he described as “unacceptable on many levels” and was given a fine and 28-day ban by the ATP. The ban was suspended for six months and Wednesday marked the end of that period.