Lee Se-dol of South Korea, a Go master who once defeated AlphaGo of Google's DeepMind in 2016 repeated the victory again in a game yesterday, even after he announced his retirement in November because he felt an "AI cannot be defeated."

The 36-year-old remains the only human player to have defeated the AI system.

Yesterday saw the first match of Lee's retirement series. The other two will happen on December 19 and 21.

With a two-stone advantage at the beginning of the match, Lee claimed victory after 92 stones after an early mistake by HanDol, his AI component, a program developed by South Korea's NHN Entertainment Corp.

But it won't be this easy for him in the latter two. The next game will be on a level field.

Lee also felt success came too easy for him, so as to question the quality of the computer.

Same as the match with AlphaGo, where an amateur player was behind the computer to place stones, 5-dan player Lee Hwa-seop was put on this position for Lee's matches with HanDol.

Lee started playing the Chinese strategy game since six years old and turned professional at the age of 12. In a career spanning 24 years, Lee scored 18 victories in international competitions and 32 wins in local events, and is considered as one of the greatest Go players of the modern era.

(With input from China Daily)