The £160,000 Bentley was parked outside Indian restaurant Zouk in Manchester city centre on Sunday evening, while the 22-year-old Italian dined with friends.
A second man joined the cheeky yob in terrorising Balotelli's car, by pulling his pants down to expose his behind before sitting on the car's back window.
Michael Armorgie, 20, an eye witness of the lewd behaviour told The Sun: "I walked past and saw this group of lads. One of them was peeing on the car.
"I couldn't believe it. One was singing Manchester United songs."
The incident comes amid increased speculation that Balotelli is on the verge of leaving the Etihad Stadium, with AC Milan heavily linked with a move for the controversial Manchester City star.
However, The Guardian also report that fellow Serie A giants Juventus are interested in signing Balotelli, who might be allowed to leave the Premier League champions on loan for the remainder of the campaign.
Juventus are believed to have offered €20million for his signature, but Citizens boss Roberto Mancini is holding out for closer to €23million.
Irrespective, the striker is keen to return to his homeland and is willing to take what represents a small pay cut regarding the terms on offer, which are €5million a year tax-free, plus a sizeable signing-on bonus.