After finally saying “yes” to rehab and undergoing treatment at London clinic The Priory, the new tour was to be her triumphant comeback.

But she was heavily booed for being an hour late and stumbling around the stage in front of 20,000 fans at Belgrade’s Kalemegdan Park.

Eyewitness reports had her saying “Hello Athens,” and things sort of went downhill after that.

“She dropped the microphone, mumbled through her songs and occasionally disappeared, leaving her band to keep on playing,” one concertgoer said.

Serbian media described the concert as a “scandal” and a “disaster,” with newspaper Blic calling it was “the worst in the history of Belgrade.” Blic posted a clip from the concert on its website, and a note that said: “Listen if you dare.”

London publicity company Outside Organization released a statement saying Winehouse decided to cancel appearances in Turkey June 20 and Greece June 22, claiming it would be “worked out as soon as possible” whether she would make the next scheduled date in Spain July 8.

The statement says she felt that canceling the shows was “the right thing to do.”

“Despite feeling sure that she wanted to fulfil these commitments, she has agreed with management that she cannot perform to the best of her ability and will return home,” it explained.

“Everyone is aware from the beginning that Amy Winehouse is a high cancellation risk,” said Nick Hobbs from Istanbul-based Charmenko, which booked the tabloid star to Athens’ Ejekt Festival June 22. “There’s a natural tendency to believe that this time it will be different.”

“I know we were very excited to be a part of this tour,” said Baris Basaran of Pozitif Productions, which lost its Istanbul show at Kucuk Ciftlik Park at a couple of days notice. “We were fully aware of the risks but still decided to get involved.

“Amy is a great talent and it was worth taking the risk. This is not something that comes and hit you out of blue; you know there are risks involved when you book the act.

“It is a gamble where you lose or gain big time – unfortunately we lost this time,” he said.

Winehouse recently spent a week at a rehab program in London. Her 2006 breakthrough album Back to Black won five Grammy Awards, but her music in recent years has been overshadowed by her drug use and run-ins with the law.