Chess Game Logic Puzzle

The World Champion Chess Match of 1921 was held at a resort in the US Virgin Islands and pitted against each other those two masters, Yeti and Zugswang.

The winner won seven games and lost six. They took turns playing white, with Yeti having white in the final game which decided the match. The black pieces won five times.

Who won the match?

Martin Hollis.

Click for the answer to this logic puzzle.