A Google-developed supercomputer bested a South Korean Go grandmaster for the second time on Thursday, taking a commanding 2-0 lead in a five-game series that has become a stunning global debut for a new style of "intuitive" artificial intelligence.

After shocking the world by defeating Lee Se-dol - one of the greatest modern players of the ancient board game - in their opening match on Wednesday, the AlphaGo computer proved it was no fluke with another victory after a grueling four-and-a-half-hour encounter.

The most famous AI victory to date came in 1997 when the IBM-developed supercomputer Deep Blue beat Garry Kasparov, the then-world class chess champion, in its second attempt. But a true mastery of Go had long been considered the exclusive province of humans - until now.