After losing his third straight Go match against Google's artificial intelligence program AlphaGo Saturday, South Korean veteran Lee Se-dol said he simply didn't have what it took to win.

"I've never felt this kind of pressure," Lee told reporters after falling to AlphaGo by resignation in 176 moves. "I wasn't good enough to handle that kind of burden. I'd like to apologize (to people). I think they must have had high expectations, but I came out lethargic."

By taking the first three matches, AlphaGo, developed by Google's London-based firm DeepMind, has secured a series victory in the five-game showdown and will take $1 million in prize money. The two sides will play out the series, with the fourth game scheduled for Sunday and the final for Tuesday.

Lee, who'd predicted a 5-0 or a 4-1 win for himself, admitted he'd "misjudged" AlphaGo's capabilities.

"Looking back, I don't think I would have won the first game even if I went back," he said. "The second game went the way I wanted early on but I missed a lot of opportunities."

Lee said even though he's already lost the series, the results of the next two games could serve as "more accurate" indicators of his abilities.

Lee added that while AlphaGo has surprised him with its victories, it "clearly has weaknesses."

"I don't know if it's so great that it will send a message to humanity," Lee said. "I, Lee Se-dol, lost, but not mankind."

DeepMind CEO Demis Hassabis said he and those in his camp were "a bit stunned and speechless" over the latest AlphaGo victory, but also gave credit to the South Korean player.

"Lee Se-dol put up an incredible fight again. AlphaGo made a large territory at the bottom of the board, but Mr. Lee found some really amazing tactics to play in the territory and create a really huge co-fight," Hassabis said. "I wanted to say that AlphaGo can compute tens of thousands of positions per second, but what's really incredible is that Lee Se-dol can compete with that just with the power of his mind and ingenuity and stretched AlphaGo to its limit in the last three games."

Sergey Brin, co-founder of Google, in Seoul to watch the historic occasion, said it was "a thing of beauty" to watch Go players.

"I am very excited that we have been able to instill that kind of beauty in our computers," Brin added. (Yonhap)