To set the default team for game related reports you can set a team as "Favorite" in the team settings.
Select the team tab at the bottom of the main navigation.
Next select the team you wish to change.
Set the Favorite control to active (green).
Returning to the list of teams, the Favorite teams will appear at the top with a Star indicator.
Any team indicated as favorite will appear as the default team for reports and will appear at the top of any team lists.