Dendi was the player who lost to OpenAI’s Dota 2 bot in its first public demonstration.
The one-on-one match took place at The International 2017 in August. Dendi, the Ukrainian professional player famous for his creative Pudge play and his years with Natus Vincere, faced an early OpenAI bot in a live exhibition rather than a normal five-on-five tournament game.
The bot won convincingly, showcasing how reinforcement learning could produce highly effective decisions in a complex game. OpenAI said the system had trained through self-play, repeatedly competing against copies of itself instead of learning from a database of human matches. The demonstration was an early milestone, but it was not yet OpenAI Five: the later system coordinated five separate neural-network-controlled heroes as a team.
Another common mix-up is treating this result as a victory over Dendi’s full professional team. It was a one-on-one exhibition. OpenAI’s later public milestones involved five-player bots, amateur and professional teams, and ultimately OG, the reigning world champions.