Artificial intelligence has again prevailed over human intuition and senses.

Google DeepMind's AlphaGo on Thursday defeated grandmaster Lee Se-dol in the second round of the five-match game of Go event in Seoul.

This is the second time in a row that the AI has won against the human champion in the current historic challenge game.

The 33-year-old ninth-dan Lee declared his resignation around four hours and 30 minutes into the match. The champion from South Korea played scrupulously but used his two-hour time out almost 30 minutes before AlphaGo and was pressed to make each move in less than 60 seconds.

Professional Go players praised AlphaGo's sense of balance displayed during the match.

Three games remain between the two to determine if AI has indeed caught up with human intelligence to conquer the ancient and intricate game of Go.

The winner will be awarded one-million U.S. dollars in prize money. However, the stakes are higher than the purse; the challenge match in itself represents a significant milestone for the progress of artificial intelligence as well as the history of the game.