Liam Ritchie was convicted of assaulting Ellen Clarkson, aged 35 as she celebrated her birthday at Edinburgh event.
Mr Richie targeted the victim following an altercation between the victim and the accused’s sister.
Ellen Clarkson suffered a fractured cheekbone during the attack .
Mr Ritchie pleaded guilty to assault to injury, an amended charge following the deletion of ‘severe.’
He was given a fine of £740 by Sherrif JohnCook.