Amy Winehouse

Booed at

'Worst' Concert Ever

6/19/2011 5:50 AM PDT BY TMZ STAFF
Amy Winehouse was unmercifully booed at a Serbian concert  last night as she wandered the stage incoherently, in what the local paper called, "the worst [concert] in the history of Belgrade."

At one point Amy gets so discombobulated ... one of her background singers comes over to sing the song for her. 

Tickets to the show were roughly $57 -- a lot, considering the average monthly salary there is only about $428.

Money ... spent.