This skill likely earned Donini the nickname Il Caravaggino. Alternatively, it is possibly that he received the nickname for being, like Caravaggio, an outsider with a short fuse and known for being litigious.
This talent probably led to Donini being called Il Caravaggino. Alternatively, he might have gotten this nickname because he shared some characteristics with Caravaggio, such as being an unconventional individual with a quick temper and a history of disputes.