The Italian World No 16, who had on Monday withdrawn from the doubles due to a thigh injury, retired from his second-round match against Indian wildcard Yuki Bhambri after an hour’s play on the centre court.
The 195th-ranked Bhambri won the first set 6-1, and the scores were tied 5-5 in the second set when Fognini decided to quit the match.
The Italian became the sixth player and the third seeded star after number two Mikhail Youzhny and defending champion Janko Tipsarevic of Serbia to pull out of the $450,000 season-opener.
“I feel very bad that I am not being able to compete in this tournament,” the 26-year-old Fognini said.
“I felt okay for the last two days, but there was a lot of pain during the match.
“I really don’t know what I will do now. Whether I should go home, or go to Sydney to practice. At this stage I can’t say I will be fit for the Australian Open.
“I need to have check-ups to know the full extent of the injury, but the only thing I can do now is rest and hope for the best.”
Bhambri, 21, a former Australian Open junior champion, said he was delighted to make the quarter-finals of his home tournament even if it came through the easy way.
“That is the nature of the game,” he said. “I did feel bad for Fognini but it is important to make use of any advantage that comes my way. I thought I played well and am ready for the next match.”
Bhambri now takes on fifth seed Vasek Posposil of Canada, who secured a walk-over when Taiwan’s Yen-Hsun Lu opted out with a leg injury.
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