Antonius is a heads-up specialist. He is a regular high-stakes player online and one of the most successful, having won millions of dollars. He has played on Full Tilt Poker under several nicknames, including "Luigi66369", "CryMeRiver9" and "Finddagrind", but having become a member of "Team Full Tilt" he now plays under his real name. During his early career he also used screen names e.g. "I_knockout_U", "try_hrdr_fish" and "-ANTONIUS-" on various other poker networks. Previously Antonius was one of a team of players associated with Martinspoker.com.