OpenAI Five defeated OG in its final public demonstration.
The event took place in April 2019 in San Francisco, where OpenAI Five won a best-of-three series against OG. OG had won The International 2018, making it the reigning Dota 2 world champion at the time. OpenAI described the result as the first time an AI system had defeated world champions in an esports game.
The victory was especially notable because Dota 2 requires five players to coordinate over a long match with incomplete information, shifting objectives, numerous abilities, and a huge range of possible actions. OpenAI Five used reinforcement learning and self-play, training bots by having them compete against one another at enormous scale.
The wording “final public demonstration” distinguishes the OG series from earlier appearances. The system had already faced Dendi in a one-on-one exhibition in 2017, lost to professional opponents at The International 2018, and defeated less experienced teams during development. After the OG event, OpenAI opened a public online Arena, where people could play against or alongside the bots.