Deep Fritz, a chess-playing computer, has beaten human counterpart world chess champion Vladimir Kramnik in a six-game battle in Bonn, Germany.
Kramnik said he would like a rematch in a year or two
Deep Fritz won by four points to two, after taking the last game in 47 moves in a match lasting almost five hours.
Of the six games, Deep Fritz won two and four ended in draws.
The 31-year-old Russian, who received $500,000 (£253,000) for playing the machine, could have walked away with double if he had been successful.
After the game, Mr Kramnik said he was "a bit disappointed" but hoped a rematch could be arranged in a year or two.
"With more time to prepare, I still have a chance," he said.
In 2002, Mr Kramnik held Deep Fritz to a draw after eight games, but the chess software has since been updated, calculating millions of positions every second.
In October, Mr Kramnik defeated Bulgaria's Veselin Topalov to become the undisputed world chess champion for the first time since 1993.