Sevnety-eight players entered a single elimination tennis tournament.How many matches were played to determine the overall champ?

please help me...and if u get the answer can you explain how you got it with a rule or a pattern

2 players in final

4 in semi final
8 in quarter final etc
16
32
64 note powers of two
there can be only 64 of the 78 in this round so there must be one beginning round with a lot of byes to winnow 78 down to 64.
78-64 = 14 players must be eliminated
so there must be 7 matches in this initial round
7 + 32 + 16 + 8 + 4 + 2 + 1