Answer Happy

You are preparing a quarterfinal bracket for a
single-elimination tournament. Teams
A,B,C,D are the 4 teams in the quarterfinal. Enumerate all the
possible tournament
matchups, including the winner. The order in a matchup does not
matter.
For Example:
Round 1: {A, B}, {C, D}
Round 2: {B, D}
Winner : {B}
is the same as:
Round 1: {B.A},{D,C}
Round 2: {D, B}
Winner: B
In contrast:
Round 1: {C, B}, {A,D}
Round 2: {B, D}
Winner : {B}
Is different (because Round 1 is different)