How does he guarantee he wins or ties at least one game?

Question

A man challenges the greatest chess player in the world to two games of chess. He guarantees that he will win or tie at least one of the games for sure. To be even more cocky, the man says he will play both games at the same time.

How does he guarantee he wins or ties at least one game?

Answer 1

He has no other choice but to play the 2 games at once because he plans on using his opponent's moves in the other game.
Board 1 will be where he will go first and in board 2 he will let his opponent go first. The chess master's move in board 1 will be copied to board 2 and the masters move in board 2 will be copied in board 1.