We broke the story ... Vitaly was arrested April 12 for allegedly assaulting a woman in Miami Beach while she was jogging by herself. She told cops he jumped out and tackled her, then proceeded to punch her in the head and chest. As far as we can tell, they didn't know each other.

Photos of the alleged victim, Lily Jensen -- obtained by TMZ from her attorney, Dan Dolan -- show the extent of her injuries after the alleged attack. She required stitches above her right eye, her eyeball was bloodied, and the area around her eye socket was badly bruised and swollen.

Vitaly's facing a criminal charge of felony aggravated battery for the incident, and now, he's also facing a lawsuit from Jensen. She's suing him for battery, assault, and infliction of emotional distress claiming she was ambushed without provocation.

According to the suit ... Vitaly "jumped out from behind bushes and punched her from behind, tackled her to the ground and while straddling her, savagely punched and beat her mercilessly with a closed fist about the head, face and body until her screams for help were heard by neighbors."

Jensen's seeking damages for medical bills, pain and suffering, disability, disfigurement, loss of earnings and mental anguish.

Dolan adds ... "Ms. Jensen was the subject of an unprovoked and savage attack on Easter Sunday by somebody who seems proud of behaving in this fashion. This can't happen in Miami or anywhere and we hope that he faces the justice he deserves."