“You retrace your steps back to the path”

Answer: 32 – In a knockout tournament, the number of matches in each round is half the number of players. Working backwards from the final we can find out the number of matches in each round and wait for the sum to reach 31: 1 + 2 + 4 + 8 + 16 = 31. The first round must have contained 16 games so there were 32 players to begin with.