Ryan Tillema scored 13 of his game-high 18 points in the second half and Josh Lawrence added 12 points and six rebounds off the bench in his first action of the season after returning from injury.
The Phoenix shot 54% from the field while the Eagles were held to 35%. The Eagles got 11 points each from Joe Werner, Chris Fehrenbach and Chris Ask. Werner also grabbed a game-high 12 rebounds.
UW-Green Bay tips off its regular season at Oakland on Sunday.