Terry Evans scored 14 points and Randy Berry 13 to lead the Phoenix.
Youngstown State shot 55% from the field to Green Bay's 54%, but the Penguins widened the gap from beyond the 3-point arc, shooting 65% from three, while the Phoenix shot 30% beyond the arc. Green Bay fell two games under .500 (7-9) in league play.
In Cleveland, the Vikings of Cleveland State won their Horizon League matchup with the Milwaukee Panthers , 74-64.
Deion James had 18 points to lead Milwaukee. The Panthers are 8-7 in Horizon League play with the loss.