Artem Lobov has launched High Court proceedings against Conor McGregor over an alleged barrage of harassing, intimidating and defamatory posts on social media about the Dublin-based retired Russian MMA fighter.
Mr Lobov claims that the most damaging post about him on Mr McGregor's Twitter account, @The NotoriousMMA is where he is allegedly referred to in a song sung by Mr McGregor as being a "rat".
The High Court heard that Mr Lobov claims that the posts about him arise from other legal proceedings brought by him against Mr McGregor.