The world's reigning champion Go player has redeemed himself with his first win over Google's artificial intelligence program Sunday after three straight losses.
South Korean grandmaster Lee Sedol defeated AlphaGo in Seoul in the fourth game of the best-of-five series involving the ancient Chinese game. The computer program clinched the $1 million prize after Lee lost the third game in the match Saturday.
The 33-year-old Lee, who has won 18 international Go titles, was greeted with rapturous applause when he arrived for his post-match news conference, telling reporters he had never before been congratulated just for winning one game.
He was far more somber Saturday after losing the third match, apologizing for what he described as a "powerless display," while acknowledging that he had "misjudged" the computer program's abilities.
Demis Hassabis, the head of Google's DeepMind team, which developed AlphaGo, said Lee's win Sunday was a "valuable" tool to help it figure out the program's limitations.
Many top Go professionals commented after AlphaGo's initial wins that it displayed unorthodox, questionable moves that initially befuddled humans, but made sense in hindsight.
Google, which put up the $1 million prize, said the money will be donated to charity.
Go, which originated in China more than 2,500 years ago, is a complex game with an almost incalculable number of move options. The game involves two players who take turns placing black and white stones on a grid-shaped board. The winner is the player who manages to seal off more territory.
The most famous AI victory to date was in 1997 when the IBM-developed supercomputer Deep Blue beat then-world class chess champion Garry Kasparov.
WATCH: Lee Sebold beats AlphaGo in fourth match