Sykes has scored in double figures in 32 straight games against Horizon League opponents and in 59 of the past 61 contests.
Carrington Love added 10 for the Phoenix (16-4, 5-1), who made 29 of 57 shots (50.9 percent).
Green Bay used a 14-2 run to build a 22-10 lead while the Flames went cold, scoring just one field goal in three and a half minutes, and led 41-28 at halftime.
The Phoenix opened the second half with a 14-8 run and led 55-36 after Mays' basket. Sykes made a jumper and pair of free throws amid a 10-2 run as the Phoenix pulled away.