Go grandmaster defeats computer after three losses

A South Korean Go grandmaster scored his first win over a Google-developed supercomputer on Sunday - a surprise victory after three humiliating defeats in a high-profile showdown between man and machine.

Lee Se-dol thrashed AlphaGo after a nail-biting match that lasted for nearly five hours. It was the fourth of the best-of-five series in which the computer clinched a 3-0 victory on Saturday.

Lee struggled in the early stages of the fourth match but gained a lead toward the end, eventually prompting AlphaGo to resign.