The Rebels (11-2) earned the victory even with a sub-standard performance by leading scorer Chace Stanback, who finished with only two points and didn't make a field goal.
Quintrell Thomas helped fill the void by scoring 13 points, and UNLV came away with its second consecutive victory.
The Fighting Illini (10-1) suffered their first loss of the season after shooting just 25.4 percent. D.J. Richardson had 19 points, but no other Illinois player scored in double-figures.