A Google software programme has drawn first blood in the latest contest between man and machine, winning the first of five planned games against a South Korean champion in the boardgame Go.
The AlphaGo programme bested Lee Sedol in a little more than two hours on Wednesday, a result which came as a "surprise" to the player.
"I was not expecting to lose, even at the beginning when I was having difficulties," Lee said after the game.
He expressed his great respect for the programming experts who created his winning opponent.
"We landed it on the moon," said Demis Hassabis, chief executive of Google subsidiary DeepMind, which developed the artificial intelligence used to beat Lee.
"So proud of the team!! Respect to the amazing Lee Sedol too," Hassabis wrote in a tweet that was shared over 1,200 times.
The software adopted strategies of reinforcing its own groups of pieces while probing its opponent for weaknesses, "the same as a really good Go player," match commentator Michael Redmond was quoted as saying by Wired online.
On Tuesday after a meeting with the AlphaGo programme team, Lee admitted: "If I make mistakes, I could lose."
The 33-year-old professional Go player is eyeing prize money of 1 million dollars. Before the first match, bookmakers were offering odds of around even for the two opponents.
"We've been saying that day is coming. We're absolutely in shock," Andrew Jackson of the American Go Association said in response to the software's win.
The rules of Go, which originates in China, are easy in principle: two players try to conquer spaces with white and black stones on the board, which is divided by vertical and horizontal lines into a grid.
AlphaGo was developed by Google's DeepMind AI branch to forecast the most probable moves of its human opponent and adjust itself accordingly.
In October, the programme won a five-game match against Fan Hui, a top European player, ranked well below Lee internationally.
The five games between Lee and AlphaGo are to be played between Wednesday and March 15 in Seoul and are due to be streamed on YouTube.