NICK Kyrgios has retired mid-match of his quarter-final against Cameron Norrie at the Atlanta Open with a hip injury.
The Australian second seed was trailing the British left-hander 7-5 3-0 after 52 minutes of play when he decided he could not continue.
Kyrgios saw the trainer midway through the first set but that did not prevent the crowd booing him off court at the conclusion.
At times Kyrgios seemed disinterested in the contest with his effort in question late in the opening set before he meekly double-faulted to give Norrie the early break in the second.
Matt Ebden will fly the Australian flag in the last four after he required just 71 minutes to defeat Marcos Baghdatis.
The Australian world No. 55 broke the Cypriot’s serve three times to secure a comfortable 6-3 6-2 win over the former Australian Open finalist. Ebden is through to his second tour-level semi-final of the year as he strives for his maiden ATP Tour title.
The 30-year-old has not dropped a set in Atlanta but will face a stern test next when he faces top seed John Isner for a place in the final.
The American was pushed to three sets by German sixth seed Mischa Zverev before he prevailed 7-5 4-6 6-1, dropped just two first-serve points in the match and sending down 21 aces.
Ebden is 1-3 against Isner but won their past meeting in January at the Australian Open.
“I am definitely playing better than I was in the beginning of the year. I was struggling a little bit,” Isner, a four-times champion in Atlanta, said. “To his credit, he (Ebden) played much better than me that day in Australia. He had the home crowd on his side. It helps a lot.
“Now, I’m playing in my backyard and he beat me in his backyard. We’ll see if I can turn the tide.”
American eighth seed Ryan Harrison advanced to a semi-final clash with Norrie by beating South Korean third seed Chung Hyeon 6-7 (3-7) 6-2 7-6 (7-5). “This is exactly what the doctor ordered for me,” Harrison said. “It was a little nervy from both of us there at the end.”