Green Bay (15-3, 5-0) won its 10th consecutive game, battling back from a second-half deficit to edge UIC (5-14, 0-5).
Sykes spurred a late charge for Green Bay, beginning with a dunk at the 2:38 mark to tie the game at 63. Sykes then hit a 3-pointer to give the Phoenix a 66-63 lead with 1:51 left.
The Flames had a chance to tie the game down 67-64 with 11 seconds remaining, but turned the ball over and Sykes finished with a fast break dunk on the other end to secure the win.
Brown scored 23 for the Phoenix and Sykes had 21.