Google says its AlphaGo Zero artificial intelligence program has triumphed at chess against world-leading specialist software within hours of teaching itself the game from scratch.
The firm's DeepMind division says that it played 100 games against Stockfish 8, and won or drew all of them.
The research has yet to be peer reviewed.
But experts already suggest the achievement will strengthen the firm's position in a competitive sector.
"From a scientific point of view, it's the latest in a series of dazzling results that DeepMind has produced," the University of Oxford's Prof Michael Wooldridge told the BBC.
"The general trajectory in DeepMind seems to be to solve a problem and then demonstrate it can really ramp up performance, and that's very impressive."
