Mathematics student Nikolai Sazhin, 19, competing under the name "The President'' knocked out a 37-year-old German policeman Frank Stoldt, who served as a peacekeeper in Kosovo until recently.
The loser said he was simply too punch-drunk to fend off checkmate.
"I took a lot of body-blows in the fourth round and that affected my concentration. That's why I made a big mistake in the fifth round: I did not see him coming for my king,'' he said.
Berlin is home to the world's biggest chess boxing club with some 40 members and it is in an old freight station here that the two men settled the matter early yesterday.
The match began over a chess board set up on a low table in the middle of a boxing ring.
Stripped to the waist, wearing towels around their shoulders and headphones playing the lulling sound of a moving train to drown out the baying crowd, the men played for four minutes.
Then off came their reading glasses and on went the gloves and the mouthguards.
For three minutes they beat each other and then, when the bell went, the chess board was back in the ring and they picked up the gentlemanly game where they had left off.
It's gotta be better than watching poker. Here's a ESPN Sportscenter story on it.