The artificial intelligence created by Google and London-based DeepMind has taken a two-game lead in a landmark championship against the one of the world’s best players at the ancient board game of Go.

The AlphaGo AI defeated South Korean grandmaster Lee Sedol in another tense game, at the Korea Baduk Association in Seoul on Thursday.

The match was another tight encounter, which entered overtime before AlphaGo eventually triumphed. “AlphaGo played some beautiful creative moves in this game,” said Demis Hassabis, Deepmind founder, on Twitter. He added that 100 million people had watched the first match online, including 60 million in China.

The victory puts Deepmind on the verge of a remarkable triumph, which some experts have suggested is a decade or more ahead of schedule in the development of true, ‘thinking’ AI.

The two sides will play three more times over the next week, with the winner taking a $1 million prize. Lee will have to win every remaining match to take home the prize.

Deepmind had already defeated the European champion of Go, the company said in an announcement made in the journal Nature in January. Google purchased Deepmind for an estimated £400 million in July 2014.

The territorial 3,000-year-old game is regarded as one of the most complex that a computer could be asked to tackle, having simple rules that extrapolate out into virtually endless, intricate scenarios. Unlike chess, which can be theoretically masted by memorising an admittedly vast number of moves and scenarios, Go requires human-like intuition, thinking and forward planning to be successful.

AlphaGo combines advanced search techniques with neural networking, allowing it to both think creatively and take advantage of huge amounts of data about previously played games of Go. Using 12 ‘layers’ of AI, it selects its next move using just one element of its system while the others predict how the rest of the game will play out. Predicting the future in this way, it adjusts its strategy and moves gradually towards victory.

The development of AlphaGo is regarded as an early step towards a true artificial intelligence, which could have an incalculable impact on human lives, economics and technology.

Deepmind AI beats human champion again