NICK Kyrgios' miserable run has continued after the Australian was defeated by world No. 98 Ruben Bemelmans 6-7 6-3 6-3 at the European Open in Belgium.
Kyrgios took out a tense first set in Antwerp but faded as the match wore on, eventually humbled by the local favourite, who recorded his first ever win against a top 20 player.
The third seed appeared to be struggling with injury during the Round of 16 clash, calling a medical timeout for an apparent hip problem during the second set.
The shock loss also puts the 22-year-old Aussie's place at the prestigious season-ending ATP World Tour Finals in London in doubt.
The loss in Belgium comes days after Kyrgios sensationally quit his first-round match at the Shanghai Masters.
The world No. 20 was fined $US10,000 and stripped of $US21,085 prizemoney after walking off the court during his match against American Steve Johnson, later claiming he was injured and ill.
"Guys, I want to apologise to the fans in Shanghai and those that watched around the world on TV today," he said in a statement
"I've been battling a stomach bug for 24 hours and I tried to be ready but I was really struggling on the court today which I think was pretty evident from the first point.
"My shoulder started to hurt in the practice today which didn't help either and once I lost the first set i was just not strong enough to continue because I have not eaten much in the past 24 hours."