OpenAI Five defeated Dota 2 world champion OG in a 2019 live exhibition match.
The best-of-three series took place in San Francisco on April 13, 2019, during OpenAI’s final public demonstration of its Dota 2 project. OpenAI Five won 2–0 against OG, the reigning champions of The International 2018. It was widely described as the first time an AI system had beaten reigning esports world champions in a live, publicly streamed match.
OpenAI Five was not a single humanoid robot or conventional game-playing program. It was a team of five neural-network agents trained through large-scale reinforcement learning and self-play. The agents learned cooperation, timing, positioning, and strategy by playing enormous numbers of simulated matches against one another.
A common mix-up is AlphaStar, DeepMind’s StarCraft II system, which also defeated professional players but in a different game and setting. OpenAI Five’s achievement was specifically in a five-on-five, modified version of Dota 2.