Hayden Humes finished with 18 points to lead UIC, and Crittle scored 15. Both had nine rebounds. Gary Talton added 10 points.
The Flames (14-8, 5-4 Horizon) are 9-1 at home this season and have won three in a row in conference play for the first time in four seasons.
Keifer Sykes had 18 points to lead the Phoenix (11-11, 5-4), who had won five of their last six. Alec Brown’s 3-pointer with 1:41 left gave Green Bay a 57-54 lead, but Crittle scored with 1:07 to play to get UIC within a point, then made four free throws in the final 16 seconds.
Brennan Cougill scored 11 points for Green Bay.