At last, human Go champ beats AI

A South Korean Go grandmaster on Sunday scored his first win over a Google-developed supercomputer, in a surprise victory after three humiliating defeats in a high-profile showdown between man and machine.

Lee Se-Dol thrashed AlphaGo after a nail-biting match that lasted for nearly five hours -- the fourth of the best-of-five series in which the computer clinched a 3-0 victory on Saturday.

Lee struggled in the early phase of the fourth match but gained a lead towards the end, eventually prompting AlphaGo to resign.

The 33-year-old is one of the greatest players in modern history of the ancient board game, with 18 international titles to his name -- the second most in the world.

"I couldn't be happier today...this victory is priceless. I wouldn't trade it for the world," a smiling Lee said after the match to cheers and applause from the audience.

Lee earlier predicted a landslide victory over Artificial Intelligence (AI) but was later forced to concede that the AlphaGo was "too strong".

Go, played for centuries mostly in Korea, Japan and China, had long remained the holy grail for AI developers due to its complexity and near-infinite number of potential configurations.

Go involves two players alternately laying black and white stones on a chequerboard-like grid of 19 lines by 19 lines. The winner is the player who manages to seal off more territory.