"American Idol" alum Haley Reinhart took the stand in her battery case, but her defense fell woefully short -- she was found guilty of hitting a bouncer.
TMZ broke the story ... Haley was arrested last July for punching a bouncer during a bar brawl that left one of her friends bloodied ... prompting him to sue one of the bouncers.
Haley took the witness stand in her own defense Monday, but the judge said her answers were "evasive, argumentative and sometimes implausible" ... according to the Chicago Tribune. She was ordered to pay a $500 fine, but the conviction could be wiped from her record if she keeps her nose clean for 2 years.
Haley tells TMZ, "I didn't see it going this way. The judge was wrong in his interpretation and had a cold and unfortunate perspective on the case."