Chalk one up for the machines. AlphaGo, a program developed by Google's DeepMind unit, defeated one of the world's top players in the board game Go in the first of five matches Wednesday, marking a huge milestone in the field of artificial intelligence.

Lee Sedol, an 18-time, 9-dan champion from South Korea, was forced to admit defeat after three-and-a-half hours, with 28 minutes and 28 seconds still remaining. There was a lot of publicity behind the match, with it being broadcast live on Youtube and local television, which provided frequent updates.

Go is an ancient Chinese game that involves two contestants moving black and white stones on a square grid, with the objective being to capture the most amount of spaces in the board. AI had already bested world-level players in games like chess and checkers, but no one thought that it would be possible in a game like Go, which requires high level of intuition and evaluation.

With that in mind, Lee, 33, as a grandmaster in the ancient Chinese game, expressed shock over his loss. In fact, prior to the match-up, Lee had predicted a 5-0 whitewash.

"I didn't think AlphaGo would play the game in such a perfect manner," he said after the match. "I would like to express my respect to the programmers for making such an amazing program."

This is the second major accomplishment that AlphaGo has achieved in the face of those who thought that it wasn't possible. Despite the program being fed 30 million moves from professional Go players so it could adopt its own strategies through reinforcement learning, i.e. trial and error, experts estimated that it would take at least a decade before the AI could clinch a victory in Go.

They were proven wrong when AlphaGo defeated European champion Fan Hui last year, but Lee is an entirely different beast who Demis Hassabis, chief executive and co-founder of DeepMind, which built AlphaGo, expressed pride in defeating.

"We landed on the moon," Hassabis said in a tweet after the victory. "So proud of the team!"

While the victory is still a major one for AlphaGo and AI as a whole, there are still four matches to go in the series with $1 million at stake. The remaining matches will be Wednesday, Saturday, Sunday and next Tuesday, with AlphaGo only needing to win two more times to be crowned champion.

Even with one victory under the belt, Hassabis is not letting it get to his head, who notes that anything is possible for the remainder of the series. "It was a very close and tense game today. When we came into this match we thought anything was possible and we still think that now - there's still four games to go," he said.

Check out the monumental battle between man and machine below. Do note that it's nearly four hours long, though.